I posted this Like a month ago and it worked for everyone that used it and It seems people still are having problems so here is the solution. Hope it still works
Go to the main Carnival page. At the bottom right there is an option to click on "Booked Guest". When you click on that the next page will give you an option to fill out your "Fun Pass". Click on that and then enter your booking number, ship, and last name. Click on enter and it will bring up the information you entered. Click on "Print Fun Pass" and it will bring up your fun pass on the next page. This has worked for everyone that has tried so good luck!!!
JUST SAY YESSSS IF IT WORKS.