[Wine] White screen after some time in WoW

[Zonarius]

My problem:
After some time playing WoW (about 1-2 minutes) the whole screen turns white. Everything else seems to work perfectly, I still have sound and I still can interact with my character. I can even open a terminal (blindfolded) and type 'killall WoW.exe' to quit WoW and make the white screen go away.

wine --version outputs 'wine-1.1.37'
I use the propiertary nVidia drivers version 185.18.36
I use Ubuntu 9.10 Karmic Koala

I've tried running in windowed mode, maximized and fullscreen. I've tried with and without this registry tweak:
http://wow4wine.wetpaint.com/page/Registry+tweak+for+FPS+Boost

I've tried OpenGL and DirectX.

Nothing seems to work.

This problem hasn't been there all the time. Wine has been updated through the Ubuntu Updater this week. It seems that the white screen occurs since then.

Thank you in advance.