title: XCode: Interface Builder crashes while compiling XIB
body: <p>When i compile my app with the command line tool <code>xcodebuild</code> (XCode 4.2.1 - iOS SDK 5.0) randomly the <code>ibtoold</code> (Interface Builder) crashes. When i rerun the build everything works fine.</p>
  
  <p>The following error happens:</p>
  
  <pre><code>ibtoold[88134:107] [MT] DVTAssertions: ASSERTION FAILURE in /SourceCache/IDEInterfaceBuilderCocoaTouch/IDEInterfaceBuilderCocoaTouch-933/IBPlugin/Utilities/IBObjectMarshalling.m:499
   Details:  Interface Builder encountered an error communicating with the iOS Simulator. If you choose to file a crash report or radar for this issue, please check Console.app for crash reports for "Interface Builder Cocoa Touch Tool" and include their content in your crash report.
  Exception name: NSInvalidReceivePortException
  Exception reason: connection went invalid while waiting for a reply because a mach port died
  Exception backtrace: 
  (null)
  Exception info:(null)
  Object:   &lt;IBAssertionShim: 0x40047fac0&gt;
  Method:   -reportMarshallingFailure:
  Thread:   &lt;NSThread: 0x40010a220&gt;{name = (null), num = 1}
  Hints: None
  Backtrace:
     0  0x00000001068f42d4 -[DVTAssertionHandler handleFailureInMethod:object:fileName:lineNumber:messageFormat:arguments:] (in DVTFoundation)
     1  0x00000001068f41a4 _DVTAssertionFailureHandler (in DVTFoundation)
     2  0x00000001094f1e20 (in IDEInterfaceBuilderCocoaTouchIntegration)
     3  0x0000000109572081 (in IDEInterfaceBuilderCocoaTouchIntegration)
     4  0x00000001095720d4 (in IDEInterfaceBuilderCocoaTouchIntegration)
     5  0x0000000106087d25 (in ibtoold)
     6  0x0000000106085413 (in ibtoold)
     7  0x0000000106085120 (in ibtoold)
     8  0x000000010608502c (in ibtoold)
     9  0x000000010608ed56 (in ibtoold)
    10  0x0000000106084baa (in ibtoold)
    11  0x0000000106085b8f (in ibtoold)
    12  0x0000000106083644 (in ibtoold)
   Command /Developer/usr/bin/ibtool failed with exit code 255
  </code></pre>
  
  <p>Any idea how to solve this problem?</p>