Hi,
Yes it is a known issue. It will go away as soon as we tell the forums that it is on the new server. It is on the new server, but it does not know it is part of petflytrap.com, which is why your cookies (which store your username and password) are being lost. Sorry that's a condensed version of a more technical explanation.
Basically, to avoid logging in, when you are prompted with the screen saying you are a guest, click on _any_ link besides login, and you will be shown as logged in.
This should be fixed within the week, still waiting for one name server to point at the new petflytrap server (which is supposed to take 48 hours, but has been over a week).
Sorry for the inconvenience.