Can't download files after 'completed'

I've set up e-commerce, with the files module. I've created a test file (given it full read/write permissions) in the set directory for file products (also with full read/write permissions, so it is writable by Drupal) and created a test product using that file, with the price of $10. It has no renewal schedule. I've got CCard and COD as the payment options. The purchasing policy is "Registered Only."

I've tried to order the product, both as the admin and as a regular registered user. I've used both COD and CCard.
In each case, after I make the order, I go into the e-commerce side (as admin) to see the order:
Transaction workflow: transaction received
Payment status: pending
I change them both to: completed
(I've also tried it with COD automatically setting them both to completed.)

According to the file.module readme file, "Customers are be able to download files after the payment status has been marked 'completed' for their transaction." However, I go to the "My Files" section (as either admin or the regular user) and I always get "You have no files to download." There's nothing in the expired files, either.

What am I doing wrong? What do I need to do to get this to work?

Note: This is probably the same issue as http://drupal.org/node/143771 and http://drupal.org/node/142245