I just found out that the new Big Dig comes out on Monday... so we might end up needing a new map anyways. It removes a lot of stuff though, namely Industrial Craft 2, Red Power 2, and Mystcraft.
(If you can't tell by the bolded underlined text, Mystcraft is the mod I'll be missing the most.)
Anyways though, this whole troubleshooting deal probably contains more trouble than shooting, and may warrant a map wipe anyways.