Coupon Problem

This store seems to be operating fine on a test server, and it uses a PayPal sandbox without a problem to make test purchases. This issue is that I am trying to add a new coupon for the first time to test this feature of the store.

I am getting a "No Input File Specified" message on a separate page when attempting to "insert" a coupon WHEN the choose products box is checked. This is true regardless of whether I "require" the code or not. The rest of the form seems to be filled out properly.

This separate page has the following at the end of the url in the address bar: ".../Admin/products_Search.php?InProcess=AddToCoupon&CouponID=3".

If the above box is not checked, everything seems fine. I see the coupon detail for the given coupon created, and the new coupon is added to the list as it should.

What is interesting to me is that the coupon is still being created regardless of the above "No Input File Specified" message. I see the coupon when I view the coupons and sales list.

Now, as you would expect, the above coupons are for "all" products. When I attempt to update a given coupon by clicking "Edit products" on the coupon detail page, I get the same "No Input File Specified" message with the same kind of ending to the url as noted above.

So, I seem to be able to create coupons, but cannot attach them to specific products, just the default "all" products.

Any ideas about what I might be doing wrong?

Thanks,
Robert