Got a new iPad2 replacement last week. This Monday I had a problem in Stanza, getting an error message and unable to read books, but that went away.
Now iBooks isn't behaving. Either pages just won't turn, or it jumps ahead almost to the end. Sometimes it works ok
Not jailbroken.

With iBooks closed, double tap on the Home button to get the multitask bar. Tap and hold on any icon until they jiggle, then tap on the minus sign on the iBooks app. This will remove it from RAM and insure a clean start the next time you launch the app.

If that does not work try a restart, and a then a reset if that does not work.


Restart: Hold down the power button until the power off slider appears. Slide it off. When the iPad finishes shutting down, hold down the power button again until the Apple logo appears.

Reset: Hold down the power and home buttons until the Apple logo appears. The iPad will reboot. This usually takes a bit longer than a restart.