Right so here is the deal,
I run the latest iMac, 10.5 leopard.

2.4GHz processor
ATI Radeon HD 2400 XT graphics processor with 128MB of GDDR3 memory
1 GB RAM (supports up to 4 GB)
250 GB Hard drive

I have the newest version of CrossOver Games (7.1)
I have the latest version of Team Fortress 2 with all the patches.

Ok so i have installed TF2, but when i go to play it, it comes up with a white screen, the music plays, it flashes and stays white but the mouse appears, then it flashes the title sreen for a nanosecond and shuts down it then comes up with a box labled "Engine error" and it says "Platform Error: module failed to initialize" . so after this i did some research and found out i needed steam so i installed that and opened it through steam the same thing happens only the title screen flashes for a bit longer (2 seconds maybe) then the error message comes up.

it's really frusturating so can somone plz plz plz help me i reallly want to play.