Constantly crashing to desktop

[whorus]

I bought this game a while ago on steam, but have only recently started playing it. I've been unable to finish the first quest because it crashes in-battle, out-of-battle, while switching areas or even just while I'm looking at the screen deciding what to do next.

I've validated the files. I've reinstalled it. Nothing helps.
I've downloaded the latest nvidia drivers (I have an nvidia 8800 GTS) without making a difference. I should note that I have many other games which all run fine.

This is a screenshot of the error I get. It's alway the same message before I get thrown to the desktop:

http://bit.ly/6izBI7

Any suggestions or advice appreciated