FATAL ERROR: Renderer #0

[Soggo]

Here's what I experience with the game:
- If I lauch Amenesia, straight after I boot Win 7, it launches without problems, however after 10-15min of play, it starts becoming unbearably slow and I have to exit.
- If I try to play the game again, it gives me the "Renderer #0" error and I can't get it to work anymore, until I reboot.

I bought the game on Steam, so I believe I've got the latest version.

I'm running Win 7 with dual screens.
I've gone through the troubleshooting guide in the forum, tried to start in windowed mode, with graphical settings set to minimal, shutting down unnecessary apps,...

I've removed/reinstalled the 260.99 NVidia drivers without success. I tried reverting to the 258.96 with the same results.

So at this stage I'm puzzled: how come it works after a fresh boot, but never again afterwards and how come the game gets so slow all of a sudden... ?!?

My hpl.log is in attachment.