ActiveSync 4.5 Error

I have an interesting problem with ActiveSync. It had been working fine for
years but now it's not working anymore. Now, it connects but does not sync.
Here's what exactly happens for me:
- I connect the USB cable
- ActiveSync launches on my desktop, both my iPaq hw6945 and my desktop
chime and then the ActiveSync window on my desktop says "Looking for
changes..."
- After about 5 minutes it gives me a dialog that asks:
"The following information type on your mobile device has items that have
not been synchronized with this computer before.
Information Type: All Desktop Services"
- I select "Combine the items on my device with the items on this computer"
and click "OK"
- I then get the final ActiveSync error dialog which says:
"Synchronization cannot be completed successfully. Reconnect your device and
try again. If the problem persists, see the Microsoft ActiveSync
Troubleshooter in Microsoft ActiveSync Help on your desktop computer.

The Troubleshooter could not find any error.

Any help on this issue is welcome.

Thanks