Need help figuring out why my app is crashing when I try to switch views

Hello I am developing apps on for 4.1 and on Xcode3.2. My Apps crash when press back button . When press back back button Last class is appeared slightly than crash, with no error or warning .... Here are the code....crash on Back Function

#import "TransactionSummaryDetailViewController.h"
#import "TransactionSummaryData.h"
#import "Constant.h"
#import "DataBase.h";
#import "Common.h"
#import "YPCardHolderServiceService.h"
#import "SelectionScreenViewController.h"

@implementation TransactionSummaryDetailViewController
@synthesize table,cardReference;
@synthesize waitIndicator,transactionsummary,keyArray,valueArray,isSummaryAvailable;
@synthesize startDate,endDate;

/*
 // The designated initializer.  Override if you create the controller programmatically and want to perform customization that is not appropriate for viewDidLoad.
- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil {
    if (self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil]) {
        // Custom initialization
    }
    return self;
}
*/

-(void)getrowcount{
    if(transactionsummary.cardholdernmae !=nil){
        [keyArray addObject:@"Card Holder Name: "];
        [valueArray addObject:transactionsummary.cardholdernmae];
    }
    if(transactionsummary.cardnumber!=nil){
        [keyArray addObject:@"Card Number: "];
        [valueArray addObject:transactionsummary.cardnumber];
    }
    if(transactionsummary.debittransactioncount != nil){
        [keyArray addObject:@"Debit Tx. Count: "];
        [valueArray addObject:transactionsummary.debittransactioncount];
    }
    if(transactionsummary.debittransactionvalue!=nil){
        [keyArray addObject:@"Debit Tx. Value"];
        [valueArray addObject:transactionsummary.debittransactionvalue];
    }
    if(transactionsummary.credittransactioncount!=nil){
        [keyArray addObject:@"Credit Tx. Count: "];
        [valueArray addObject:transactionsummary.credittransactioncount];
    }
    if(transactionsummary.credittransactionvalue!=nil){
        [keyArray addObject:@"Credit Tx. Value: "];
        [valueArray addObject:transactionsummary.credittransactionvalue];
    }
}

// Implement viewDidLoad to do additional setup after loading the view, typically from a nib.
- (void)viewDidLoad {
    appDelegate = [[UIApplication sharedApplication]delegate];
    keyArray = [[NSMutableArray alloc]init];
    valueArray = [[NSMutableArray alloc]init];
    [self getrowcount];
    NSLog(@"Key Array Count is %d",[keyArray count]);
    [table setBackgroundColor:[UIColor clearColor]];
    [table setSeparatorColor:TableViewCellSeperatorColor];
    [waitIndicator setHidden:YES];
    [self setTitle:@"Summary Details"];
    UIButton *button =  [UIButton buttonWithType:UIButtonTypeCustom];
    [button setImage:[UIImage imageNamed:@"list.png"] forState:UIControlStateNormal];
    [button addTarget:self action:@selector(BacktoView) forControlEvents:UIControlEventTouchUpInside];
    [button setFrame:CGRectMake(0, 0, 76, 44)];
    self.navigationItem.leftBarButtonItem = [[UIBarButtonItem alloc] initWithCustomView:button];
    if(!isSummaryAvailable)
    {
        if([Common isNetworkAvailable])
        {
            [waitIndicator startAnimating];
            YPCardHolderServiceService *services = [[YPCardHolderServiceService alloc] init];
            YPTransactionsSummaryRequest *summaryRequest = [[YPTransactionsSummaryRequest alloc] init];
            summaryRequest.SC = appDelegate.SC;
            summaryRequest.userName =开发者_Python百科 appDelegate.userName;
            summaryRequest.valid =TRUE;
            summaryRequest.cardReference =[NSString stringWithFormat:@"%@",cardReference];
            NSLog(@"Start Date Is %@ and End Date is %@",startDate,endDate);
            summaryRequest.startDate = startDate;
            summaryRequest.endDate = endDate;
            summaryRequest.applicationType = @"M";
            [services getTransactionsSummary:self action:@selector(getTransactionsSummaryHandlers:) transactionsSummaryRequest:summaryRequest];
            [summaryRequest release];
            [services release];
        }
    }

    [super viewDidLoad];
}

//Handle the Response of getTransactionsSummary
-(void)getTransactionsSummaryHandlers:(id) value
{
    [waitIndicator stopAnimating];
    // Handle errors
    if([value isKindOfClass:[NSError class]]) {
        NSLog(@"%@", value);
        return;
    }

    // Handle faults
    if([value isKindOfClass:[SoapFault class]]) {
        NSLog(@"%@", value);
        return;
    }               


    // Do something with the YPLoginResponse* result
    YPTransactionsSummaryResponse* result = (YPTransactionsSummaryResponse*)value;
    if(result.statusCode == 0)
    {
        NSLog(@"Number of Transaction is =%d",[result.transactionSummaryList count]);
        NSLog(@"Step 1 ='%@'",appDelegate.userID);
        NSString *deleteQuery = @"delete from TransactionSummary where userid = ";
        NSLog(@"Step 1 ='%@'",appDelegate.userID);
        deleteQuery = [deleteQuery stringByAppendingString:[NSString stringWithFormat:@"%@ and cardreference = '%@'",appDelegate.userID,cardReference]];
        NSLog(@"delete query= '%@'",deleteQuery);
        [DataBase deleteDataFromTable:deleteQuery];
        NSLog(@"delete query= '%@'",deleteQuery);
        //for (int i =0; i< [result.transactionSummaryList count]; i++) 
        for (int i =0; i< [result.transactionSummaryList count] -2; i++)
        {
            NSLog(@"for loop= %d",i);
            YPTransactionSummaryDetails *transactionSummary = (YPTransactionSummaryDetails*)[result.transactionSummaryList objectAtIndex:i];
            NSLog(@"cardholdername= '%@'",transactionSummary.cardholderName);

            /*NSString *insertQuery = @"Insert into TransactionSummary(cardholdername,cardnumber,debittransactioncount,debittransactionvalue,credittransactioncount,credittransactionvalue,userid) values(";
            insertQuery =[insertQuery stringByAppendingString:[NSString stringWithFormat:@"'%@','xxxx xxxx xxxx %@',%d,%d,%d,%d,'%@',%@)",
                                                               transactionSummary.cardholderName,transactionSummary.cardNumber,transactionSummary.debitTransactionCount,
                                                               transactionSummary.debitTransactionValue,transactionSummary.creditTransactionCount,transactionSummary.creditTransactionValue,
                                                               appDelegate.userID]];*/
            //Add by sarvesh
            NSString *insertQuery = @"Insert into TransactionSummary(cardholdername,cardnumber,debittransactioncount,debittransactionvalue,credittransactioncount,credittransactionvalue,cardreference,userid) values(";
            insertQuery =[insertQuery stringByAppendingString:[NSString stringWithFormat:@"'%@','%@',%d,%d,%d,%d,'%@',%@)",
                                                               transactionSummary.cardholderName,transactionSummary.cardNumber,transactionSummary.debitTransactionCount,
                                                               transactionSummary.debitTransactionValue,transactionSummary.creditTransactionCount,transactionSummary.creditTransactionValue,cardReference,
                                                               appDelegate.userID]];
            NSLog(@"Insert Query for Transaction Summary is %@",insertQuery);
            [DataBase InsertIntoTable:insertQuery];
        }
        //Read Update Data From DataBase and Refresh Table
            NSString *query = @"Select * from TransactionSummary where userid = ";
            query = [query stringByAppendingString:[NSString stringWithFormat:@"%@ and cardreference = '%@'",appDelegate.userID,cardReference]];
        NSLog(@"select query= %@",query);
            NSMutableArray *temp=[DataBase getTransactionSummaryTableData:query];
            if([temp count] > 0)
            {
                transactionsummary = (TransactionSummaryData*)[temp objectAtIndex:0];
                [keyArray removeAllObjects];
                [valueArray removeAllObjects];
            }
            [self getrowcount];
            [table reloadData];

    }   
}


-(void)viewDidAppear:(BOOL)animated
{
    CGFloat navBarHeight = 50.0f;    
    CGRect frame = CGRectMake(0.0f, 20.0f, 320.0f, navBarHeight);
    [self.navigationController.navigationBar setFrame:frame];
    [super viewDidAppear:animated];
}

-(IBAction)BacktoView
{
    NSLog(@"in back function..TrasactionSummaryDetail");
    SelectionScreenViewController *screenView=[[SelectionScreenViewController alloc] initWithNibName:@"SelectionScreenViewController" bundle:nil];
    [self.navigationController popViewControllerAnimated:YES];
    [screenView release];
}


- (UITableViewCellEditingStyle)tableView:(UITableView *)tableView editingStyleForRowAtIndexPath:(NSIndexPath *)indexPath{
    return UITableViewCellEditingStyleNone;
}
- (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView{
    return 1;
}

- (CGFloat)tableView:(UITableView *)tableView heightForRowAtIndexPath:(NSIndexPath *)indexPath
{
    return cellHeightForGroupedTable;
}

- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section{
    if(section == 0)
        return [keyArray count];

    else        
        return 0;

}

- (NSString *)tableView:(UITableView *)tableView titleForHeaderInSection:(NSInteger)section{
    NSString *title = nil;
    switch (section){
        case 0:{
            //title = @"Summary Details";
            break;
        }
    }
    return title;
}

- (CGFloat)tableView:(UITableView *)tableView heightForHeaderInSection:(NSInteger)section {
    if ([self tableView:tableView titleForHeaderInSection:section] != nil) {
        return tableHeaderHeight;
    }
    else {
        // If no section header title, no section header needed
        return 0;
    }
}

- (UIView *)tableView:(UITableView *)tableView viewForHeaderInSection:(NSInteger)section {
    NSString *sectionTitle = [self tableView:tableView titleForHeaderInSection:section];
    if (sectionTitle == nil) {
        return nil;
    }

    // Create label with section title
    UILabel *label = [[[UILabel alloc] init] autorelease];
    label.frame = CGRectMake(20, 6, 300, 30);
    label.backgroundColor = [UIColor clearColor];
    label.textColor = HeaderTextColor;
    label.shadowColor = HeaderTextShadowColor;
    label.shadowOffset = CGSizeMake(0.0, 1.0);
    label.font = HeaderTextFontSize;
    label.text = sectionTitle;

    // Create header view and add label as a subview
    UIView *view = [[UIView alloc] initWithFrame:CGRectMake(0, 0, 320,60)];
    [view autorelease];
    [view addSubview:label];

    return view;
}


- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath{
    UITableViewCell *cell = nil;

    NSString *cellIdentifier;

    cellIdentifier = @"SectionsTableIdentifier";
    int row = [indexPath row];

    CGRect nameLabelRect = CGRectMake(19 , 8, 240, 29); 
    CGRect cardlabelRect = CGRectMake(19,31,240,15);
    UILabel *nameLabel = [[UILabel alloc] initWithFrame:nameLabelRect]; 
    UILabel *cardnumber = [[UILabel alloc] initWithFrame:cardlabelRect];
    cell = [tableView dequeueReusableCellWithIdentifier:cellIdentifier];

    if(cell == nil){
        cell = [[[UITableViewCell alloc] initWithFrame:CGRectZero reuseIdentifier:cellIdentifier] autorelease];
    }

    // Remove all subview from cell content view
    for (UIView *view in cell.contentView.subviews){
        [view removeFromSuperview];
    }


     [cell setAccessoryType:UITableViewCellAccessoryNone];
    [nameLabel setTextColor:firstLabelFontColor];
    [nameLabel setFont:firstLabelFont];
    [nameLabel setFont:firstLabelFontSize];

     nameLabel.textAlignment = UITextAlignmentLeft; 
     nameLabel.text = [NSString stringWithFormat:@"%@ : %@",[keyArray objectAtIndex:row],[valueArray objectAtIndex:row]];

     [cell.contentView addSubview: nameLabel]; 

     cell.selectionStyle = UITableViewCellSelectionStyleNone;
    [cell setBackgroundColor:[UIColor clearColor]];
    [cell setBackgroundColor:TableViewCellColor];

    [nameLabel setBackgroundColor:[UIColor clearColor]];
    [cardnumber setBackgroundColor:[UIColor clearColor]];

    [cardnumber release];
    [nameLabel release];
    return cell;
}


/*
// Override to allow orientations other than the default portrait orientation.
- (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation {
    // Return YES for supported orientations
    return (interfaceOrientation == UIInterfaceOrientationPortrait);
}
*/

- (void)didReceiveMemoryWarning {
    // Releases the view if it doesn't have a superview.
    [super didReceiveMemoryWarning];

    // Release any cached data, images, etc that aren't in use.
}

- (void)viewDidUnload {
    // Release any retained subviews of the main view.
    // e.g. self.myOutlet = nil;
}


- (void)dealloc {
    [table release];
    [waitIndicator release];
    [keyArray release];
    [valueArray release];
    [transactionsummary release];
    [super dealloc];
}


@end

DOn't you think that this

-(IBAction)BacktoView
{
    NSLog(@"in back function..TrasactionSummaryDetail");
    SelectionScreenViewController *screenView=[[SelectionScreenViewController alloc] initWithNibName:@"SelectionScreenViewController" bundle:nil];
    [self.navigationController popViewControllerAnimated:YES];
    [screenView release];
}

should be this

-(IBAction)BacktoView
 {
    NSLog(@"in back function..TrasactionSummaryDetail");
    SelectionScreenViewController *screenView=[[SelectionScreenViewController alloc] initWithNibName:@"SelectionScreenViewController" bundle:nil];
    [self.navigationController pushViewController:screenView animated:YES];
    [screenView release];
 }

It seems you are trying to push a controller on stack but accidentally you popped.

just put

[self.navigationController popViewControllerAnimated:YES];

in your BacktoView method and then check your previous page(SelectionScreenViewController)