-[CFRunLoopTimer release]: message sent to deallocated instance 0x4e281f0

i have done chat app on xcode 4 without errors , but when i lunch the app it takes 4 seconds then it show me thread error ( SIGKILL & EXE_BAD_ACCESS ) at main.m file

    int main(int argc, char *argv[]) {
NSAutoreleasePool * pool = [[NSAutoreleasePool al开发者_开发知识库loc] init];    
int retVal = UIApplicationMain(argc, argv, nil, nil); // thread
[pool release];
return retVal;

}

then i tried NSZombieEnabled and i get this < -[CFRunLoopTimer release]: message sent to deallocated instance 0x4e281f0 > what i can do ? please

You're either releasing an instance of CFRunLoopTimer (or possibly NSTimer, they're toll-free bridged) twice, or you're releasing an instance that you don't own. If you use the analyzer in XCode, there is a good chance it will flag the incorrect release for you; otherwise you'll have to look through your code wherever you use these classes and verify that you release appropriately.