The new itunes won't let me put my songs on!!

Hi so recently i just got my laptop fixed and thought that it would be a good idea to upgrade everything on it however, when i tried to drag my songs from limewire to Itunes 9.1 it wouldn't let me? I read that some people just downloaded the old one again but when I do that it comes up with something about it can't open up because it was created by a newer version.

Please help Brett