I just had the same issue.

49 groups (also from an old W3T board import), the closest thing to a special character in the group name was a few parentheses and one equals sign ... the browser "dead hung" after just a couple of seconds of attempting to load Group Management using Opera 9.23 (Build 8808).

It opened just fine (albeit after several seconds, hehe) in IE 7.0.5730.11

Jesus was an architect previous to his career as a prophet
All of a sudden, I found myself in love with the world
So there was only one thing that I could do
Was ding a ding dang my dang a long ling long