unable to update songs on ipod in itunes

I have a 4th generation nano, and have been unable to make any changes to it via iTunes the last few times I have tried. I read somewhere that it could be because I have AVG on my laptop (I am using a Windows laptop). I have tried temporarily disabling AVG, but the playlists are still greyed out so I am unable to edit the playlists. I am also unable to add new albums to the ipod. Can anyone help please.