This sound like a problem on your end with available RAM, have you tried the utility I posted to extend memory on 64bit machines? (See the forum navigation thread.)I've recently got back into playing DoC, but now I face constant crashes every now and then. The crashes oftentimes happen after the first turn, usually by the second. The longest I've went through without crashing is probably 7ish turns. It doesn't crash into desktop or anything, it simply froze and had its audio repeating, it happens for all starts.
I've tried everything up to the point I deleted the game entirely and re-installed them to no avail.