[cogs] Screen always black, and OpenGL error 0x0502 at Material::useEffect 1

[Ryan C. Gordon]

> I can't manage to play the game on Linux:
> https://bugzilla.icculus.org/show_bug.cgi?id=5171.
>
> Can anyone help me please?

Someone mentioned this happens to them when running the game at higher 
screen resolutions.

(also, if you're not using build #3, you should. Build #1 had problems 
with the fglrx driver.)

--ryan.