Are you sure the appropriate network driver is being loaded? I've noticed that it may appear to be fine, other than the mapping errors, however, it never really checks in to the DS server.
Also, if your password has more than 8 characters that could also cause a problem. I would also try to map via the IP address instead of the name to ensure it's not a name resolution problem (i.e. \\192.168.1.1\express).
Hope that helps at least a little bit.