I'm logged in at both, it says so on RP. It also won't let me logout, which I'm assuming is because i'm logged in on the forums.
I've deleted all cookies and then started again, logged into FBB, which then also logged me into RP. No joy though, same error as before when trying to access the admin panel.
As for cookies, what are the RP ones called? I've got FBB, rsi and _utmc/b/a, are any of them for RP?