>53: ConnectionOpen(CreateFile())
>connection failed.
>and
>6: specified sql server not found.
The selected IPC mechanism cannot locate the server that you're trying to connect to.
Are you using NT Auth. in a multi-domain environment? Maybe you need a trust between the two domains.
If you're using named pipes, SQL Server ships with two utilities that can help diagnosis these types of problems: makepipe.exe and readpipe.exe. Check the BOL for more info on those.
If you're using TCP/IP, try to PING the server from the workstation.
-Mike