Found this info in another post and it worked for me! At least I can sync with no errors using DM 5. If I feel lucky I'll update to DM 6 and see if that now works at home.
1) Make sure your Blackberry is disconnected from your computer
2) Start DM (Desktop manager) and on the upper right hand corner select Options
3) Select "Data Folder Options"
4) Select "Use this specified folder"
5) Right mouse click on the datapath and hit "select all" and copy
6) Hit Start and select Run
7) Paste data path into run and hit ok
8) Blackberry folder will open
9) Find the "Intellisync" folder - select it and delete it
10) Connect your Blackberry
11) Go to your DM's main menu - select "Synchronize"
12) On the left hand side - select Configure Synchronization
13) Select "Synchronization" button
14) When done - select Synchronize (Upper left corner)
15) On the synchronize screen - select only "Synchronize Organizer data" and "Update device date and time"
16) now select "Synchronize"