Hi Nick,
I have the same problem.
Using:
PHP Version 5.4.32
Joomla 3.3.0
CommunityBuilder 1.9.1
Error Message:
Service Temporarily Unavailable
The server is temporarily unable to service your request due to maintenance downtime or capacity problems. Please try again later.
But It only happens when editing users in CB and nowhere else!
it's just the same for me, i can edit list's field's and so one but when i try to edit a user information i get the error message.
You can have access to the backend if you want.