I have the same problem, when iTunes tries saving to the music library it never stops. All my music is "ghosted" when i try to edit the info, so it seems like iTunes is not allowed to write to the disc. I checked the folder in explorer and it is not write protected anymore (was when i installed iTunes though)
I am running Win 7 x64 with the iTunes library on a separate document drive F:
I tried running iTunes 'as administrator' and now i could edit the info in the songs, but iTunes still isn't able to write to the library.
It seems like a problem that a lot of people are experiencing.
http://social.technet.microsoft.com/Forums/en-US/w7itproappcompat/thread/7e7510c8-6864-471c-a2dc-5e2b42b5084b/?ppud=4&wa=wsignin1.0&ffpr=0