Thanks for your suggestion. I tried it and obviously had a lot work information to work with.
I have now finally discovered that there is a serious TCP/IP problem on my notebook. SQL Server 2000 is running with the correct drivers installed and changing the TCP/IP port in the network utility doesn't help either. On doing a port scan i found that only the application server as well as the windows default ones that get used gets displayed. SQL Server as well as a few other applications that open ports don't get listed under TCP/IP. Reinstalling it and resetting the TCP/IP stack did not fix the problem either.