Cannot access iTunes store from iPad app

Hi

I downloaded the Marvel comics app and wanted to make a purchase but keep getting "Cannot connect to iTunes store".

I have reset the iPad (holding down both buttons until the screen goes black, then the Apple logo appears), signing out and back in to iTunes, signing out and back into the app, shutting down the iPad then restarting, turning restrictions on and off and turning WiFi off then back on. I have contacted the developer who told me it's a issue with iTunes.

I see a few others are having a similar issue, and have tried a lot of things I did -- but I still can't purchase thru the Marvel app.

For what it's worth, I'm in Australia but I was able to download the Marvel app from the AU store so I assume I can make purchases(?)

Help?

Thanks.