when i do a live test with a product set up for just a download and the download/model sku associated to ANY the transaction completes ok and i am returned to the completed page
when i associate the file download to a attribute and choose that at the product/features/download/model sku (File Download) i am returned to the cart page
both instances show file in accnt file download area and both get email notifications
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i tried again and the 1st time it worked with just a standard download and i am returned to the completed page
tried attribute download and i was returned to cart
tried one more time on standard sku(ANY)download, no attribute, and was returned to the cart page
Sad to know that this problem occurs in fresh installs too 
Disappointing to hear that we are still not able to find a hint on cause of this problem.
Ryan can involve a little deeper in this problem, and ask us to try some techniques such as adding echo statements in certain php files or ask us to watch out for certain events in server logs or suggest to diagnose this problem using firebug (extension for firefox) to find the cause of this problem,
But he is reluctant in helping us in this problem
Joined: 08/31/2007