It turns out that I only resolved part of the problem. I can now access my file shares again, but the local workstation still shows as "unauthenticated". However, I am starting to wonder if this is a bug in Windows 7 since it doesn't seem to have an impact on anything…
Bern, I am running a web server, a mail server and a database on my windows server. I know that I can probably do the same on Linux, but my knowledge in Linux isn't the greatest and so I feel that I would just set myself up for trouble... ;)
On the plus side I also have trixbox which runs on linux in my environment as well. However, that also gives me more than enough trouble at times... ;)
I figured I should update my findings here in case somebody else runs into the same problem.
Thanks again to everybody trying to help!
Cheers,
Jens