Pertti - I get exactly the same error as you now do when I use the latest release, and have been getting it for quite a while (during most of the RC releases as well).
I find it only happens on more complex maps - on the smaller test maps I don't have any testing or build errors. I'm very interested in seeing feedback on this topic as this is my only concern in the entire product.
I have the most recent DirectX (and general Windows XP) updates, and my PC is fairly high spec so I'm not seeing resource issues during the compilation stages (although the processor gets hit hard, there is still a lot of free memory).
Feedback gratefully received on this one.
Whatever.