Checkout will not complete

I'm trying to setup a simple cart for my website, I've built the site in DW CS5. After I ran the all eCart wizards, I could add an item to the cart, but when I hit the CHECKOUT button I would be immediately redirected back to the cart page (viewcart.php).
I noticed that the "get contents" function on the checkout.php page was below the "redirect if empty" function. I reversed the order of the functions, and I could proceed from viewcart.php to checkout.php. I had the same problem when clicking CHECKOUT on the checkout.php page. The same functions (get contents and redirect) were out of order in the checkout_success.php page, I reversed them but was unable to proceed with the checkout.

I tried deleting everything from the site that had anything to do with WebAssist, ran all eCart wizards again, still the same problems.

I set up a new site & database, ran all eCart wizards, this time the above mentioned functions were in the correct order, and I could take the checkout process successfully through, until I would click CHECKOUT on confirm.php. When CHECKOUT is clicked the checkout_success.php is being immediately redirected to confirm.php, no data was sent to the database either.

Attached are the checkout files for the first mentioned site, and all files from the second "fresh" site.

Thanks in advance for any input!