Setting Max Time Controls?

I just tried to challenge someone to a game and received this error message:

You can find this on your online chess settings page at http://www.chess.com/home/echess_settings.html

Right.  Thanks.  I just found that.  I had mistakenly thought that was not a reference to time controls of challenge games, but rather a filtering of people who could challenge me based on their average time per move.  But obviously that's not correct!

But another question, since I've got you here...
I'm not clear about the difference between administrators and super admins.  Can you clarify that?  As my group grows I'm looking for help administering it, but wouldn't want someone to take it over, delete people, etc.  Obviously I wouldn't make someone an administrator that I didn't trust, but you never know...

Additionally, can an administrator or a super admin unlock and edit forum posts that they did not author or lock?  E.g. I have an important sticky and locked post that I created but would like to be able to have an assistant un-stick and edit it.  Is that possible?

Thanks in advance!