Network Reachability error: in iphone os 4

my project was buied in os 3.0

but now i want to do some changes with os 4.

so when i run my project in xcode 3.2.4.

i get those errors......

ld: warning: in /Users/abc/SystemConfiguration.framework/SystemConfiguration, missing required architecture i386 in file

ld: warning: in /Users/abc/libz.1.2.3.dylib, missing required architecture i386 in file


Undefined symbols:
  "_SCNetworkReachabilityScheduleWithRunLoop", referenced from:
      -[ReachabilityQuery startListeningForReachabilityChanges:onRunLoop:] in Reachability.o

  "_SCNetworkReachabilityGetFlags", referenced from:
      -[Reachability remoteHostStatus] in Reachability.o
      -[Reachability isHostReachable:] in Reachability.o
      -[Reachability isNetworkAvailableFlags:] in Reachability.o
      -[Reachability isAdHocWiFiNetworkAvailableFlags:] in Reachability.o

  "_SCNetworkReachabilityCreateWithAddress", referenced from:
      -[Reachability reachabilityRefForAddress:] in Reachability.o
      -[Reachability isNetworkAvailableFlags:] in Reachability.o
      -[Reach开发者_如何转开发ability isAdHocWiFiNetworkAvailableFlags:] in Reachability.o

  "_SCNetworkReachabilityUnscheduleFromRunLoop", referenced from:
      -[Reachability stopListeningForReachabilityChanges] in Reachability.o

  "_SCNetworkReachabilityCreateWithName", referenced from:
      -[Reachability reachabilityRefForHostName:] in Reachability.o
      -[Reachability isHostReachable:] in Reachability.o

  "_SCNetworkReachabilitySetCallback", referenced from:
      -[ReachabilityQuery startListeningForReachabilityChanges:onRunLoop:] in Reachability.o

ld: symbol(s) not found
collect2: ld returned 1 exit status

Try removing the frameworks from your project directory and add the updated ones for iOS4.

I made the new project with same name and add all class and view by drag and drop.

and add other all framework.

now its working