Cannot open Palm Desktop after new Treo

[bigtimetopbanana]

Hi guys.... any pearls of wisdom would be gratefully accepted...

I've installed Palm Desktop on my PC, and on syncing the Treo it correctly creates the new user and creates the directories and files on my PC.

However, when I then try to switch to that user on the PC, it comes up with:
"Error: Failed to open Data Book database"
"Error: Failed to open Address Book database"
"Error: Failed to open To Do List database"
etc, etc.

I've done the obvious, like check to see if the files are read only... but the sync managed to create these files, so I'm not sure of the problem.
And yes, I've re-installed Palm Desktop. I'm running Palm Desktop v4.1 by the way.

Any ideas?