Has anyone had this problem and found a fix? I am using WMP 11 and have tried syncing to both a Pocket PC with WM2003SE and my Smartphone with WM2003SE, each using a 2GB SD card. The sync works fine for about 10-20 minutes or 30-50 songs, then all of the syncs start failing. To fix this issue I have to disconnect the Pocket PC and then re-establish the ActiveSync connection (via USB).
This is annoying as I need to sync around 700 songs And have to remember which ones synced correctly and which ones failed.