i modified the plist for itunes genre artwork and tried o save it but it says that it cannot be saved. for the record i added another genre with artwork and i had already tried to duplicate it but the duplicate button was gray and uncickable. help?!
It sounds like you don't have the proper permission for editing that file. Try this: copy the file you want to edit to your Desktop, edit the copy on your Desktop, save it, copy it back to where you found it, it'll ask you for your password, click "Replace". That's all.
You'll need to restart iTunes for it to reread the plist file. It may take a computer restart. Recheck the plist after saving to ensure the changes stuck.