Errors when building iPhone app in Xcode

I get this error (and 27 others) when trying to build my application. I'm not sure what has changed to cause this, but i have no clue what the error actually means? This is an example of where i am calling appDelegate = (iTourAppDelegate *)[[UIApplication sharedApplication] delegate];

  ".objc_开发者_StackOverflowclass_name_UIApplication", referenced from:
  literal-pointer@__OBJC@__cls_refs@UIApplication in MapViewController.o

Another example

  ".objc_class_name_NSString", referenced from:
  literal-pointer@__OBJC@__cls_refs@NSString in ListTableViewController.o

I tried a clean build but no success.

Any ideas how to solve?

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Solved by searching for FRAMEWORK_SEARCH_PATHS under /* Begin XCBuildConfiguration section */ in project.pbxproject (in xcodeproj bundle) and removing that entry. Back up first! Thanks to Sean Roehnelt of SO for this answer on a different post

Build error Missing required architecture i386 in file