bugger. i caught this:
"EmpirePoker and PartyPoker track new accounts by IP address, so if you've been actively playing at PartyPoker from a specific IP address within the last 30 days, EmpirePoker will not allow you to establish your LOGIN NAME and PASSWORD from that IP. " at
Flop Turn River - exactly what you said.
i didn't do a full fledged search, but if there was a pack of people that would know the workarounds, i would expect these guys to be on the list:
bonus whores message boards
best of luck with it. if you do find a solution, could you post it?