A few days ago my iPhone did not sync files when I connected it to my Mac. Instead, my Mac displayed a 13019 error message.
A Google search revealed a simple solution that was published in an Apple Knowledge Base article:
1. Select the iPhone or iPod touch in iTunes under Devices.
2. Click the Music tab and under the Sync music option, choose Selected playlists.
3. Deselect the Voice Memos playlist.
4. Click Apply and then click Sync.
The aforementioned problem can affect an iPod touch, iPhone 3G, or iPhone 3GS running iPhone OS 3.0.