Thanks, Tom -- Please go to the window that's treating you as not being logged in, and hit the Control-F5 combination in order to refresh the window. The resulting window should show you as being logged in (i.e. "Tom Poje" appearing towards the top right part of the window, rather than "Sign In").
Regarding the viewing of new posts, I'm not sure what would have been causing the issue last week (when we were still running the previous version of the message boards software), but please let me know if you're able to view new posts when you've (1) logged in, and (2) clicked on "Activity" (a new tab that's in the menu towards the top of the page). I think you'll be pleased at all the ways you can view new and other recent activity (including posts) on the message boards!