I'm getting an odd Error 500 message when I try to publish entries in one of my blogs. A bit of background - upgraded my install from version 3.34 to 4.1 recently. I had some MySQL issues that seemed to get fixed with some phpMyAdmin changes, but I'm still getting the dreaded Error 500 message when I try to either publish a new entry, or "republish" an old entry with saved changes. New entries seem to save fine as long as they are left in "unpublished" mode, but once I go to "publish", I get the error.

I was starting to think there might have been an issue that cropped up with the phpMyAdmin changes, but then I forgot that I had another blog that exists within the same MySQL database, so I went there and made a new entry and published it as well as "republishing" an older entry with changes - no problem at all.

Any ideas on how to troubleshoot the original blog? I've never seen an Error 500 that wasn't global to the whole installation, so I'm stumped here. Obviously I wouldn't think it's a permissions problem, since the other blog seems fine. Probably going to end up being some brain-dead issue on the one blog, but I've been going back through filepath syntax, mt.cgi file components, etc. and can't find a thing.