MPGH was just updated to the latest version of vBulletin and plugins such as reputation, moods, mentions, thanks and some others haven't been re-installed yet. The URL redirection has also seem to be affected too.
For example, a URL like this no longer works:
https://www.mpgh.net/forum/2-general/
https://www.mpgh.net/forum/616-call-d...-unlocker.html
You must use this instead:
https://www.mpgh.net/forum/forumdisplay.php?f=2
https://www.mpgh.net/forum/showthread.php?t=618450
Take note of the #2 which is the forum ID and the #618450 which is the thread ID. Use the forum index page to navigate through the sections instead of using the bar at the top which is currently broken:
https://www.mpgh.net/forum/index.php
Be patient, it will eventually be fixed. It was worse when we transitioned from vBulletin 3 to vBulletin 4 because many plugins that we used were no longer supported.