I have an application that uses a tab bar and whenever it launches it crashes and gives me the following error and stack trace:

2010-04-22 16:15:03.390 iCrushCans[59858:207] *** Terminating app due to uncaught
exception 'NSUnknownKeyException', reason: '[<UIWindow 0x3e051a0>
setValue:forUndefinedKey:]: this class is not key value coding-compliant for the
key rootViewController.'
2010-04-22 16:15:03.392 iCrushCans[59858:207] Stack: (
    29680731,
    2425423113,
    29839809,
    305768,
    304309,
    2957847,
    4641908,
    29583663,
    4636459,
    4644727,
    2805842,
    2844630,
    2833204,
    2815615,
    2842721,
    37776729,
    29465472,
    29461576,
    2809365,
    2846639
)

Thanks in advance!