When running a search on one portal, it gives an error and generates this exception. It seems to work fine on other portals using the same AF install though. Anyone ran into this before?

Turn full-text off then back on in the Active Forums control panel.

Turning off full-text search, no problem. Turning it back on again appears to be a problem.
Clicking on "Save" does nothing, I even let it sit there for about 10 minutes. Changing other settings works as expected, just the full-text search won't turn back on.

Ok, that means something changed on the server. Either you don't have permission to create a new full-text catalog, you don't have permission to access the current catalog or full-text just isn't enabled on the server or database. You'll have to do it manually through management studio. There are few topics in the forums about what you need to do on the server side.

Okay, thanks, I'll go look those up.