There seems to be a few problems in the newest file you posted. I can see that the store order summary and details server behaviors have the tigger set to any form post, these should both be set to same page post.
Also, I did not see any checkout on the pages, did you remove this? It seems that there are a few things going on, it might be a good idea to backup these pages that you have now and create a new set of checkout pages with the wizard. After this test out the pages and post back with any issues that you discover.