I recieved my ipad from my school, and they had told us we could put music onto our devices.
Apparently you got some bad information. since the iPad is a school owned device, you should probably ask them what to do because that is some kind of profile that is set up on the device that only they can deal with - or so it seems to me.
You'll have to take it in and have them allow that...because right now it has 'Administrative Rights' which were set by the computer used to set the device up...that computer had administer rights and did not give them to the user of the iPad.
The only other option would be to restore the device:
But that will erase everything else on it, and since it's not on your library your won't be able to put it back on.