First off, the back button that I believe you are referring to is the one that is located under the trackwheel.
Second, when 15-20 minutes it stopped loading, were you in a spotty coverage area, or by chance did you have a call that was incomming? I kind of like to compare these to the old dial up modems with call waiting. Sometimes (from my experiences) it won't ring but all of a sudden you will get a voice mail pop up. Sometimes it will suspend the connection and your phone will actually ring. Sometimes it just freezes up. Guess just depending on whatever mood your berry is in at the time.
As far as being connected and IE saying it wasn't, the only thing that I can recommend is just try your connection again. I have used Internet Explorer, Firefox and Opera on my Laptop when connected through the Blackberry, and Firefox is the best that I have come across so far with a Blackberry connection.
Hope this helps. Lemme know.