Here's a quick tip:
You need to make sure all your access as well as admin roles have owners defined. Without owners you will receive a 500 error message on your browser when executing the View Access Role or the View Admin Role espectively looking up that role which has no owners.
The log file will show the following error message:
2014-03-18 10:43:06,377 ERROR [ims.ui] (ajp-0.0.0.0-8009-1) Exception during page display: