Not that anyone really cares, but I think I found the source of the problem. The web designers at D* appear to have used an Active-X component of flash player to display the adobe pdf file in the window on the screen. Well guess what! Firefox, for very serious security reasons, does not support Active-X. So, the only browser that will work on this page is one that supports Active-X components and you have "Allow Active-X components" clicked on in the tools section. Really bad design. But, if you want your pdf files, as I do, use IE or some other browser that supports Active-X and it will work.
The folks at D* are still clueless as to what the problem is on this. They are stuck at saying you need to have javascript allowed -- which is another well known security hole. But, such is life.
So, if you are having problems downloading D*'s pdf bills, just use your IE browser and all is well.
I am so wedded to Firefox I didn't even think someone in the commercial world would limit their customer experience this way. Really newbie level programming.