Hi there and welcome to the forum!
Sorry that you are having trouble with your pages jamming up.
Try to do these immediate fixes and see if it helps:
-Force the iBooks app to close by doing a 4 finger swipe upward or hitting the home button twice to get the multi-task bar. Long press the app until it shakes and press the red circle with the negative sign. Than reopen the app and re-test.
-restart the iPad by pressing the power switch and slide the lock switch to turn off. Turn back on and re-test.
Good luck, let us know if this helped.