Originally Posted by ArmorDog
I haven't had a chance to try in on the Wifi yet. But, for what it's worth, a similar thing happens on the Touch.
I open the book, use the navigation slider to scroll to page 100, and everything locks up. I had to hold the power switch until it turned off, then turn it back on. Everything else was unresponsive. I'm going to crack open the epub and see what's going on.
Let me know if you find something. I'll put a bug report in for calibre if somebody can figure out what needs to be done differently.