Have you been to their site? It's been a long time but it seems to me there was an update for MOO way back when. Not sure...
Note: DirectX 9 is not a new version. And it doesn't come installed with Windows 7.
Given the age of MOO, (Win95 days wasn't it?) you're probably going to have to install DX9.
(I just looked it up: released in 1993. Wow!)
If it works without it, then don't bother, though. Keep it simple...
I hunted around among some boxes but couldn't find my old copy of MOO. Shame on you! Now you've done it!