[SOLVED] Itunes – Computer not authorised?

Plugged my iPod in today to sync some music, and now i get a window saying “This computer is no longer authorised for applications that are installed on the iPod”
I thought, errm ok, so clicked ‘Authorise Computer’ but when i did it, it said my computer was already authorised Anyone know what the hell’s going on?
When i deauthorise my computer it says it will delete 27 applications (iTouch by the way) and when i authorise it again it wants to delete 10.
The iPod is jailbroken, but i’ve never had any trouble before and i haven’t changed anything
Halp
Answer #1
Solved
Turns out it said that cos the 10 applications needed 2.1 firmware (im on 2.0)