I was more than happy, when Apple included option to read iBooks on desktop devices as well. However, it seams to be a problem with PTP iBooks widgets. Everything works out of the box in iPhones/iPads, but does not work on iBooks desktop version. The screen goes black and when clicking the right mouse button, this message is shown:
"Movie not loaded... About flash player 11.9.900.117..."
Could it be, that desktop version uses flash instead of html5? Or the html code must be altered for to use in desktop version?