I'm not 100% sure this will work but if you're comfortable editing the registry, it's worth a try.
Get a good registry editor for the Pocket PC (I recommend
this one) and navigate to HKLM\Software\Microsoft\Windows CE Services\Partners and find the key relating to your computer (probably P1). If the PName value isn't the name of the computer you want to synchronize with, change it to this. Shutdown the registry editor, soft-reset and try again. It should work this time. If not, I'm as stumped as you are.
