No probs Keith.
I examined the download to check that it actually contained valid data. The file contains a lot of zero's at the start and end; sandwiched in between is hexadecimal values that make up the BIOS update. The start of the information (bulk non-zero's) start at the hexadecimal offset (from the start of the file) at 8000 so a cursory glance at the raw data might have made the ISO file to appear as invalid/empty (only containing zero's).
Not sure how far you have taken the update process - if you burn the file to a CD using Nero or a similar utility you should be good to go.