Problem with establishing connection to SQL Server from DMZ

Hi.

I am developing a web application that connects to a MS SQL Server(2000) database. The SQL server resides within the corporate internal network. The web server resides within our DMZ. TCP port 1433 in the firewall between DMZ and the internal network is open. I can telnet to the database on that port. The problem is I can not set up a DSN to that database, nor can I connect to it via my ASP application.

We logged the network traffic and it seemed that the web server was trying to access UDP port 137 also. I shut down the microsoft network client service and the "netbios over TCP/IP" service. So the web server should not try to access that port now. But we still can't establish a connection to the database from the web server.

So, do you think this a driver problem? We use the MS SQL Server driver that was installed with SQL Server. This is obviouslyt not a firewall issue, since we can connect to the database with telnet. What else could be wrong?