I had to do that too with Players Only
and Poker World awhile back too. You cannot have the same name at both sites. And I was vague about this before, but I believe the reason you cannot be logged into both is that their freerolls
(and MTTS & SNGs & cash games(????)) are shared. So if, for instance, you are in a 3000 person freeroll at Poker World, of that registered list, many may have logged in through Players or another site within that network. Someone correct me if I'm wrong. I've never looked that carefully at what was being offered at the same time. I also used to play at UB and Absolute simultaneously before the merge.