Soldato
Yes you would need to restore it from iTunes/Seas0nPass to do a complete wipe/re-jailbreak and then follow the updated XBMC install guide to install Frodo fresh.
This is a great reason to run a MySQL library. Drop an advancedsettings.xml in the right place and your entire library is back in all of the blink of an eye instead of having to rescan. Backup your sources.xml too to make things even quicker.
I've been playing with mysql on my synology nas this week but I'm buggered if I could get it to work correctly. After 2 days of faffing about I turned it off and went back to my previous settings. I followed the wiki guide for setting up the server and still couldn't get it to work. I'll just settle for re-scanning for the files again.