An uncaught exception was raised

/Applications/SuperJumpWorld.app/Contents/MacOS/SuperJumpWorld
2011-12-29 12:48:12.353 SuperJumpWorld[39355:60b] MacGLView loaded
2011-12-29 12:48:20.282 SuperJumpWorld[39355:b703] *** Assertion failure in -[GameScene addChild:z:], /Users/raimundeiler/Desktop/Mario/Mac/Version_1_0/libs/cocos2d/CCNode.m:407
2011-12-29 12:48:20.283 SuperJumpWorld[39355:b703] An uncaught exception was raised
2011-12-29 12:48:20.283 SuperJumpWorld[39355:b703] Argument must be non-nil
2011-12-29 12:48:20.285 SuperJumpWorld[39355:b703] (

/Users/raimundeiler/Desktop/Mario/Mac/Version_1_0/libs/cocos2d/CCNode.m:407

I havent this user

R.Zaitsev about Lep's World, v1.0