Serving files across subnets through Samba?

Quick rundown of my network: --OD and Samba running on 10.4.10 Server --2 10.4.10 Servers sharing files (authentication done through OD) --All servers and my MacBook Pro located on subnet 172.20.1.X --All client machines on subnets 172.20.2.X through 172.20.4.X If I fire up Windows on my MacBook Pro, and click Start > Run > \\fileserver.domain.com\ I get a login prompt, whereupon I can authenticate as any of my OD users and access files on the server. If I do the same thing from a client machine on one of the other subnets I get a login prompt, but when I put in a valid username and password, the login prompt disappears and then reappears, this time with the username field filled in with [Windows name of machine]\[OD name that I just put in] and the password field blank. If I try this three times, the person's OD account is then locked out. How can I fix this?