Scott, are you sure you have advanced the film far enough for the numbers to show up? Also, if the paper leader came loose from the takeup spool, you may be turning but NOT advancing the film. You may want to pop the back off in a dark room (or closet, etc) and feel if the paper is advancing when you turn the advance knob. You may also need to jam some cardboard under the takeup spool, to make sure it engages properly. Double over a flap from the box the film came in, should work for you. For more Holga hints check Squarefrog.com and Flickr.com
I hope this helps you, and welcome to the Apug website.
Paul