Currently Being ModeratedOct 1, 2013 3:24 PM (in response to Leventhal68)
Perform a Reset on the iPad (different from just restarting).
Hold down on both the Sleep and Home buttons at the same time for about 10-15 seconds until the Apple Logo appears. When you see the Apple logo on the black screen, let go of the buttons.
After the reset, go to "Settings" then "iBooks". Go to "online content" and turn it on. Try downloading from iBooks again.
Hope this answers your question!