[Wine] Steam: Fatal Error: VGUI_Setup failed

[Schmiddehy]

Hi,

I recently installed steam in wine and everything was working fine. I managed to install a bunch of games and even played and completed portal. However, steam has stopped working now and is giving me the error 'Fatal Error: VGUI_Setup failed'. I had to update my graphics driver due to the one in the ubuntu additional drivers menu not working properly (so I updated it manually) and since then I get this message in steam. Does anyone know how I can fix it? I've tried uninstalling and reinstalling both steam and wine and I've also tried wine 1.4 and 1.5 but keep getting the same error.

If it helps, this is the info about my computer:

Ubuntu 12.04 64bit
AMD 64 Athlon X2 processor
4GB ram
NVIDIA GeForce 8800 GTS graphics card (this had a recent problem with a driver update in April, and I assume that this is the driver that is still offered on the additional drivers application in ubuntu since it gave the same problem after working for a day, the driver I am now using is 295.53 which is the newest on the NVIDIA site.

This all happened in the course of a day - 
1) I installed steam and it worked but games wouldn't start
2) I installed graphics driver in 'additional drivers' app and games started working, though start-up of computer had slowed slightly
3) turn on computer this morning and start up was incredibly slow in Unity 3D, freezing and basically unusable. (this is the problem with driver 295.40 on 8 series cards apparently) 
4) manually update driver - desktop working fine, steam no longer starts.

any help would be much appreciated, I got very excited at the prospect of finally being able to play my steam games in ubuntu yesterday.