While that may not be it, I wonder why you have such an old ActiveSync. Sorry, but that's only clue I can offer given the details. XP should have issues. I'd install at least XP SP1.
I am running Windows XP Home edition on the desktop, connected to a Compaq 3900 series PDA. Using Active Sync 3.5. My computer died so it was rebuilt with a new motherboard. When I went to reinstall the connections to the PDA it refuses to sync tasks, contacts and addresses but does sync the xcel and word files.
I have reinstalled Outlook 2002 (came with the PDA) to no avail.
Here is the error message I get:
"Synchronization cannot start because this desktop computer cannot access necessary information. Restart this desktop computer and snychronize again. If the problem persists and the destop computer is running Micorsof Outlook 2000, open Outlook 2000, click Help and then click Detect and Repair. Otherwise, contact your network administrator."
I have restarted the computer numerous times, I have also done the "Detect and Repair" listed on the outlook menu.