I've no idea why you can't download the images directly from the cameras but, even if you could get the software to work, connecting your camera directly to your PC is a very slow and unreliable way to transfer images.
Simply get hold of a USB card-reader. They only cost a few pounds. (Try Tesco Extra or Asda, or buy online:
http://www.ebuyer.com/product/54461 )
Then you can simply drag-&-drop (or copy-&-paste) files from your memory card to your PC, in the same way that you can transfer files from floppies, CDs or between folders). You'll transfer the files much faster and more reliably; you can completely forget about the file transfer software which came with the cameras, as this will be redundant.
Chris