I have the plugin (2785) installed on 3.04 and 3.1 RC2. Both installations are Multisite, use Month & Name permalinks, and the bbPress Twenty Ten theme. When I click on a forum name in 3.04 it takes me to my front page, but 3.1 RC2 responds as expected. I’ve tried deactivating and reactivating the plugin and theme with the same outcome, but switching permalinks to the default fixed the problem.
Any thought of combining the bbpress twenty ten theme you are developing with twenty ten for buddypress that Andrea is working on? That would be ideal for me, and I assume several others, because we are planning on using both plugins.