我有一个现有的应用程序，适用于Xcode 4.0的其他人。我打开这个应用程序时，我有Xcode 4.02和xcode崩溃。有时，它只是挂起，我必须'强制退出'Xcode。其他时候，它会给我一个“内部逻辑错误”窗口并显示以下错误。
**ASSERTION FAILURE** in /SourceCache/IDEFoundation/IDEFoundation-287/Framework/Classes/Model/SourceControl/IDESourceControlTree.m:2548
Details: (addedItem) should not be nil.
Object: <IDESourceControlWorkingTree: 0x202020900>
Method: -mergeStatusOperationResults:forLocalStatusOnly:
Thread: <NSThread: 0x2025f3900>{name = (null), num = 16}
Hints: None
Backtrace:
0 0x0000000100949773 -[IDEAssertionHandler handleFailureInMethod:object:fileName:lineNumber:messageFormat:arguments:] (in IDEKit)
1 0x000000010006d394 _DVTAssertionFailureHandler (in DVTFoundation)
2 0x000000010055e1c1 __78-[IDESourceControlWorkingTree mergeStatusOperationResults:forLocalStatusOnly:]_block_invoke_0 (in IDEFoundation)
3 0x0000000100005fdc __38-[DVTDispatchLock performLockedBlock:]_block_invoke_0 (in DVTFoundation)
4 0x00007fff822cd51b dispatch_barrier_sync_f (in libSystem.B.dylib)
5 0x0000000100005f83 -[DVTDispatchLock performLockedBlock:] (in DVTFoundation)
6 0x000000010055ccd3 -[IDESourceControlWorkingTree mergeStatusOperationResults:forLocalStatusOnly:] (in IDEFoundation)
7 0x00000001005db64c __77-[IDESourceControlWorkingTree updateLocalStatusForDirectory:completionBlock:]_block_invoke_01137 (in IDEFoundation)
8 0x00007fff822d42c4 _dispatch_call_block_and_release (in libSystem.B.dylib)
9 0x00007fff822b2e32 _dispatch_queue_drain (in libSystem.B.dylib)
10 0x00007fff822b2c94 _dispatch_queue_invoke (in libSystem.B.dylib)
11 0x00007fff822b283e _dispatch_worker_thread2 (in libSystem.B.dylib)
12 0x00007fff822b2168 _pthread_wqthread (in libSystem.B.dylib)
13 0x00007fff822b2005 start_wqthread (in libSystem.B.dylib)
我最近将Xcode从版本3升级到4.02。我已经测试了其他几个项目，它们似乎在4.02上运行良好。所以，我知道Xcode安装正确。请帮我弄清楚我做错了什么。