Update: I told Dave and he fixed it. Issue resolved.
Firstly, go here: http://www.mpgh.net/forum/profile.php?do=editoptions
EDIT: Wait, I'm having the same problem. Looks like MPGH is falling apart after arun's hostile takeover. Once we get Dave back, the problem should be fixed. Until then, just write the markup yourself. That's what I always do anyway. You can use Google to find standard bbcode markup.
[url=www.google.com]Google[/url] = Google
[b]Google[/b] = Google