I have Joomla 1.5 loaded and have also loaded in Community Builder. I have tried to load in both FireBoard and Agora as forums, and in both cases I get an error:
I have looked at my CGI error logs and there is nothing there.The server encountered an unexpected condition which prevented it from fulfilling the request.
The script had an error or it did not produce any output. If there was an error, you should be able to see it in the error log.