Same problem. Brand new iPhone 3.0 / 3GS 16 GB - 14 GB remaining so I know I have plenty of space!
I was wandering around in some sub-level room (can't remember where now), just started to play and I am on this black page. At first I thought I hit a wall in a dark room but no amount of turning or looking up or down is doing anything. Then I read this post and remember I got a calendar alert in the middle of the game. I was definitely not looking at a book or a page, actually just walked into a room and turned around.
Is resetting the iPhone my only recourse to reset the game? What will I lose if I do this? Do I need to re-sync it?
Argh! Hopefully the new release is released soon! I was just getting going!