Hi I am trying to purchase Nelson study commentary in the commentaries section but when I click the buy now thing it brings up the connecting to iTunes window then after several seconds returns to the buy now screen.

Nit sure if this is a bug or server problem but wanted to let you know

We've asked Apple about this, but they haven't been able to help us. If you email support, we can help you purchase this.

Right will do, it's weird other purchase options are working fine, just not the one I want, typical lol.

Yeah, it's odd. Certain items just don't work using certain versions of Mantis. So the NSB won't work in the free version of Mantis, but will in other versions, and vice-verse for one or two other titles.