I have users connecting to a share at logon and I am not sure as to where the files reside. This is the path: sys on 'metrometer.local\root\group' when I ping metrometer.local, I find its on a local server here, but I cannot find the files in that share anywhere on that server. Where would they be?

You went to that servers control panel and looked at the listed shares? Was "sys" one of them? That path does not look right to me. "metrometer.local" is your DNS namespace. This indicates a DNS misconfiguration to me. Appears you don't have host and ptr records for you dns server in dns or if you do they refer to 'metrometer.local' not the servers name. If you can't figure out where "sys" is located and you are an admin on the server place a file called yourname.txt and then do a search of all drives for yourname.txt. If its on that server you will find it and then you will know where the share is located. Imagine the power of knowing how to internet search http://www.lib.berkeley.edu/Teachin...

I realized this is being shared through DFS. They have a firewall in between two groups at the same company. For some reason, when a client tries to connect to the DFS share, it prompts him a user name and password to connect. If I try on a PC on the other side of the firewall, I can map to this share using his credentials. What could be causing him unable to connect to the DFS share?

Do both sides belong to the same domain? Same forest different domains? Imagine the power of knowing how to internet search http://www.lib.berkeley.edu/TeachingLib/Guides/Internet/FindInfo.html

Yes, one forest. Windows 2003 Domain and a Windows 2000 Forest

You really mean one 2003 forest that contains a domain which is made up of 2000 and 2003 servers, right? Because you can't have a 2003 domain in a 2000 forest. This is important to understand and may directly effect what is going on. If someone brought up the 2003 server as a DC without running adprep on the 2000 forest schema master and having the 2003 server join the forest as a DC.. you have two forests of the same name. Where are your servers? All on one side of the router? Imagine the power of knowing how to internet search http://www.lib.berkeley.edu/TeachingLib/Guides/Internet/FindInfo.html