Morten: I can confirm now that the 3GB switch is really needed for this game in 32 bit Windows (with 4GB RAM), in order to run it without random crashes.
But, I am convinced that 2GB should be enough for an adventure game... not all textures have to be loaded into the memory at once. Maybe using some disk caching / virtual memory could help.
P.S. I have looked at HWinfo32 just after playing DFC (v. 1.1.1 / 188.8.131.52), and it seems that only single CPU core was used. The other one was cold. Does the application run better with only single core support?