This problem is specific to Internet Explorer & D7
In Orca forum. Can create a group successfully, then can create a forum within that group. Once created, you cannot open the group to access the forum for editing as an admin. Clicking on the group does not expand it to allow access to the forums within the group. You can, however, expand the group and access the forum as a user.
This only happens for me in ie8. Firefox does not seem to be affected by it.
Windows XP Pro, & IE8 logged in as admin.