I am having a heck of a time figuring this out. I can access my Filmaker Pro 6 Server from a Mac remotely and local with no problem however from a Windows copy of Filemaker remotely I have no access. My copy of FM Server is behind a firewall with the ports 5003, 50003, 50006 being forwarded to the server. Are there additional ports that need to be configured for Windows? Any help would be appreciated.

No, if you can access it from the Mac remotely it should work from Windows. The connectivity is all TCP/IP which is platform agnostic.

Check if the Windows machine is running its own OS firewall.

You can also close ports 50003 and 50006, they don't do anything for FMS 6 (which is 5.5).

If you are trying to do remote administrationon a PC, you have to install that feature on your PC workstation and it's located on the Server 5.5 CD. Click on install and then choose custom or modify (can't remember which) then you can install that remote server administration on the PC. On the Mac, it comes when FileMaker is installedm but the PC is separate.