We are in the process of setting up a fax server. We are using XP Professional and have installed Windows Fax Console Version (5.1). So far we are not able to configure more than one line at a time with this software, is this a know issue?

The built in Windows Fax software does not support multiple lines.

Here are two fax server solutions that can support multiple lines:

http://www.equisys.com/products/zetafax/

http://www.esker.com/fax-servers/