See if this article helps:
http://groups.google.com/group/microsoft.public.visual.sourcesafe/browse_thread/thread/d7433001dc2e5a57/4d983482903894d8%234d983482903894d8?sa=X&oi=groupsr&start=0&num=3
Matt says near the end of the page this is due to some broken OLEDB configuration, and his solution was to replace MsDart.dll with a copy from a good machine and to re-register OLEDB dlls.
This post also indicate a MDAC/OLEDB registration issue
http://groups.google.com/group/microsoft.public.vsnet.vss/browse_thread/thread/32be359650a1497e/a26e927ffd6059a7%23a26e927ffd6059a7?sa=X&oi=groupsr&start=1&num=3
so if Matt's solution doesn't fix the problem I'd try uninstalling and reinstalling MDAC (I think you'll find it on VS .NET prerequisites CD)
Alin