Hmmmm I am trying to remember i think you gotta go to one of the save points and go to a different world
then you might get your membership card (well idk i hope the advise works)
First off, Anime78 should go to the Kingdom Hearts 2 message board for help for that game.
Secondly, you get your membership card the first time you go to Hollow Bastion,
and lastly, yes, you need to go to a save point to get on the gummi ship.