You have downloaded the imgages under Windows, right?
Try this: http://downloads.activestate.com/con...d5sum/Windows/
If it is not such a big problem, try downloading the image again, but without using bittorrent, just direct ftp download.

In the folder on the server, where the ISO image is, should you find this file: KNOPPIX_V3.4-2004-05-10-EN.iso.md5.asc
There are the md5sum that you should have with your image.