I'm trying to run Garry's Mod on a mac, but...

Asked by Theotherkid (889) November 8th, 2009 from iPhone

I got an application called crossover games that allows mac users to play popular windows games. I then installed steam, followed by downloading Garry’s Mod. When I try to launch Garry’s Mod, however, I get an error saying “hl2 has encountered a serious problem and needs to close.” After this message is shown, Gmod refuses to start. Can anyone help me fix this?