[iTunes] "Can't Update iPod" message

[Carol F. Bruml]

Tonight, I docked my 40-gig clickwheel iPod, and shortly thereafter, got the
message from iTunes that it could not update the iPod because there is not
enough free space to hold all of the items in the selected playlists.

This does not make sense to me, since iTunes says there is 15.44 gigs of
free space on the iPod.

My entire iTunes Library is 39.85 GB, and I am quite certain that there is a
minimum of 6 GB of that that is not in the selected playlists, and should
not be synched with the iPod.

So, what do I need to do to make the iPod update completely and correctly?

BTW: it seemed to update just fine, until I added a Smart Playlist, which
was really just a combination of all of the lists that were already on the
iPod. Why should adding a list, that does not contain additional music,
cause the iPod to suddenly think it does not have enough room for an update?

Carol