It's really sad that so many games are becoming incompatible with Win2k for no good reason. In many cases, it's because of some compiler setting that causes the game to be built expecting certain functions to be present in other DLLs, even if the functionality is never used and the function is never called. This is pretty much all Microsoft's fault, and it's within the realm of possibility that they are releasing SDKs on purpose that cause these incompatibilities to occur, taking advantage of overworked game programmers who don't have time to test for Win2k compatibility.
In fact, there have been cases where I could hack up the symbol table in a DLL (such as the XInput DLLs) so that the correct function name could be imported from the DLL (one present in XP's version but not Win2k's version). The hack would have led to a crash if the function were ever called, but the games run fine, so obviously the incompatibilities in those cases are completely artificial.
Normally, I would, er, adjust things on my own to get this game working on my desktop Win2k machine, but when playing on GameTap, I can't do things that modify Sam & Max game files since they're on an encrypted volume.
Anyway, since it appears that the problem here is similar to the problems I've had in the past where a slight change to the build settings can fix things for all us Luddite Win2kers, I'm really hoping that Telltale will throw us a bone here and release an update, even though Win2k isn't officially supported