Direct access to the forum is the issue, as opposed to accessing it through the CMS framework.
We used to have a separate forum, store, and news site. Now they are all linked, with one login. However, I left access to the old forum directory open for people who didn't update your links when I made that announcement, or just didn't see it.
Access to this forum is best made by going here:http://poetryslam.com/index.php?option=com_smf
Going to forums.poetryslam.com or poetryslam.com/forum will still work (so bookmarks and links didn't break), but you will experience cookie issues. When I upgrade the CMS next I'll move the directories around and set up some mod_rewrites to fix that, but that's not going to happen until closer to Slammasters.