To access any content (info pages, posts, or materials) in a PRIVATE iTunes U course, you have to use an iOS device (iPad, iPhone, or iPod touch). PC or Mac computers WILL NOT do it.
Our college has a private iTunes U authentication server. We keep it because of this exact limitation of PRIVATE iTunes U COURSE. Our Private iTunes U collections can be assessed on iOS devices or any PC or MAC computer.
This limitation is only on PRIVATE iTunes U courses.
For the Public iTunes U courses, however, the users can access some of the Info pages (course description and outline) and the Materials (video, audio, PDF, web links) on a PC or MAC computer.
Hope this helps.