I have never had a problem with a program called FASTSUM (http://www.fastsum.com/).
Make sure you are checking for the correct file, in my case the file was '811_q_image.tgz'.
The checksum list on the Netapp site contains checksum details for '811_e_image.tgz' (think it was 'e') and other zip files.
NOW site is down for maintenance so I can't check right now.