Sounds like xfs, the X Font Server, isn't running.
Do a ps ax and look for xfs in the list of processes that are running. If it's not there, start it up (perhaps just a reboot is sufficient for that; if not, try something along the lines of /etc/rc.d/init.d/xfs start). But it does look like the modprobe fixed the original problem, at least, so that's good.
If you can't figure out XFS, then just edit the FontPath entries in your config file so that instead of unix/:7100, you have the individual directories under /usr/X11R6/lib/X11/fonts listed.
Oh yeah, and if a firewall is running, try disabling it to see if that helps. The firewall might be blocking localhost port 7100, maybe.