in my test website I use WordPress 3.4.1, bbPress 2.1.2, permalink set to /%postname%/ and a handful of plugins which I have deactivated to avoid conflicts.
Basically when I try to submit a topic or a reply from the frontend, as a subscriber, I get the ‘white page’. The topic/reply is created, as admin I can edit it from the backend, but it doesn’t have the permalink and the edit permalink button. Also, the topic/reply is counted but it is shown in the corresponding frontend lists (obviously clicking on it gives a 404-page not found) only if I’m NOT logged in as admin.
If I write a topic/reply from the frontend while logged in as admin, I don’t get the white screen but still the topic/reply is created whithout permalink.
If I add as admin a topic/reply from the backend then the permalink is created and everything works. Also the topics/replies added from the backend are the only topics/replies that are shown in the frontend list while logged in as admin.
Thanks a lot!