[howiem]

You may have the same problem I had - because I tried using the iPhone version on my iPad, the iPad now counts as two separate clients. If any single client hasn't been synced recently, the number of Zip files explodes.

If you go to your Mac version, go to Preferences > Sync > Show Clients, you should be able to see if the iPhone version on your iPad is registered. If so, remove it, sync all your devices, and all should be fine again.