iPod iPod Classic - Contacts won't all load

I'm trying to sync all my contacts onto my 120 GB iPod classic. I did a restore and the iPod re-synched.

I get the message "2675 of 3258 contacts were loaded. Only a limited portion of your contacts could be loaded due to the amount of content on this iPod."

(Prior to my restore, only 2451 contacts loaded.)

Here's what's on the iPod:
Audio: 30.87 GB
Video: 3.18 GB
Other: 577.7 MB
Free: 77 GB

The AddressBook folder in Users/MB/Library/Application Support is 120.4 MB.

Seems like there's plenty of room on the iPod. What gives? What can I do?

Thanks.

More Strangeness with contacts & iPod

Well, I did another sync -- this time "2481 of 3258 contacts were loaded." Very strange -- each sync leaves me with a different number of contacts on the iPod but not all of them, even though there's a lot of free space (76.98 GB this time)