I have a feeling you get the same problem that I was experiencing on linux, it probably doesn't like starting in FullScreen.
(Absolly could tell you where to find drive_c, I don't use Mac, so I can't say for sure where wineskin puts it.)
Go to drive_c/Program Files/Renegade X/UDKGame/Config/ and edit the UDKSystemSettings.ini with any text editor. Search for FullScreen, should be in the top 20-30 lines or so. Change the value to false and then try starting the game again.
THANKS SO MUCH DUDE THIS WORKED =D