Thanks for your reply. In response to some of your follow-up questions, here are some answers:
Q from you: How do you know your purchases are hidden? That is not a very common thing. The first thing I would suggest is to view your purchase history using your current Apple ID.
My answer: I can see the hidden purchases under My Account in ITunes. Here's a screen shot:

Here is a screen shot of the original purchase: Please note that my Apple userid is not there

When I click on unhide in the hidden purchases window, the item does in fact disappear, but it doesn't appear anywhere else. I would expect it to appear in my ITunes library, but it doesn't. Do I have to refresh my library? Is the fact that I use "ITunes in the Cloud" help in troubleshooting?
So - what can I do? Clearly, I paid Apple for these products. Now I can't access them. What is my next step, Apple?
Thanks again.