Those CD's are great for the "nuts and bolts" researcher like you. But they are huge files and the problem may not be your computer. It may be the program that you are using to open them with.
I had the same problem when I used photoshop and the other programs which nomally will open such files and got the same error message.
I finally had to download a 30 day trial program of Adobe Illustrator to get them to open. So the good news is that the problem may not be your computer. Once you get the files to open with the trial version you can even print off the maps a piece at a time with you printer.
The bad news is that Adobe Illustrator is an expensive program at $500. And after the 30 days trial period is over you are out of luck as far as using that program until you buy the program or something simular. Unless you can find some way to print the maps to paper.