Today, I tried to integrate the DiscussionPlugin into my Trac 0.10.3 sandbox. But I must notice, that the DiscussionPlugin seems to be incompatible with the version and/or the WebadminPlugin. The discussion plugin where not found several times and disturbed the webadmin. So my last chance was to uninstall the plugin from the plugins folder. Tomorrow, I will try to install it on the python path to make it globally available. Maybe it works better this way.