hey russell,
you can define what users are allowed / not allowed to do in the ACL section which you can find at easydiscuss backend -> acl
when you're there you should see the available joomla groups, now click on a group - for example "registered users" (as that's most of the time the default group) and you are presented with all sorts of rules that you can turn on or off: http://screencast.com/t/jIg2uDfie5U

this should take care of your problem, hoewever if this doesn't solve it feel free to get back to us and provide us with your joomla site details and ftp access so that we can investigate this directly at your site.

hope that helps and have a nice day