greenkoi wrote: I installed a fresh copy of Joomla 3.3.2 and CB 1.9.1 on the same server. I can edit users on this installation.
So this confirms that your hosting environment and CB has nothing to do with error cause..
Any thoughts?
Confrims that something you have added to the working installation has broken the save.
Inspect with Firefox error console to see if there is any javascript broken on the save page - this might help you pinpoint the culprit.