checksum doesn't match-what now???

[EKatzenberger]

Novice who doesn't know squat.
downloaded the sled 11 iso file and burned to dvd as per novell download site instructions.
downloaded the md5sum checker from nullriver (thanks to this forum) software and ran the program (in windows vista) and the outcome was the sums don't match.

what do I do now??

Thanks in advance for your help.

Ed