Level Editor Problem

[ZIGGALAWIGGALA]

Hello! I have a problem with the level editor. It has no problems in-game, but when i'm going to "build" the level, it won't "build". I have a Mac OS X 10.6.8, 2 GHz Intel Core 2 Duo and 2 GB of RAM. Anyone who has same problem? If someone have the answer, don't be afraid to answer this thread.