[Wine] Steam games wont start

[kittens123]

I have latest Wine on Ubuntu 11.10, and i want get my 3 Steam games running. The problem is that, i try to start a game, it says "Prepairing to start (game name)" and then it closes, game wont start. I would like to get Garry's Mod, Portal and Portal 2 working. I have ATI HD 4250 and i have installed drivers from Additional Drivers in Ubuntu. What i should do?