I'm sorry to report that I found a major bug in the MMM omod Installer script. It affected anyone who do NOT have an FCOM setup and choosing to rename the MMM.bsa. In that case the MMM.bsa was not extracted to your data folder at all. This is now fixed in v. 1.2 that is up, both at http://planetelderscrolls.gamespy.com/View.php?view=OblivionMods.Detail&id=5583 and http://www.tesnexus.com/downloads/file.php?id=24646.
So if you have installed MMM (without FCOM, but possibly with Fran or OOO) and experienced crashes and/or missing meshes, the reason is the missing MMM.bsa. Either donwload and install the new script or manually extract and copy the MMM.bsa, renaming it to be identical to your main MMM.esp ("Mart's Monster Mod.bsa", "Mart's Monster Mod for Fran.bsa" or "Mart's Monster Mod for OOO.bsa")
Sorry for the trouble
