This has nothing to do with SFS installation.
Error 21 (not enough sectors found) means that you either try to read beyond the end of the disk (is it larger than 1.6gig ?) or the disk has a real physical read error (magnetical fault).
In the first case you should check and adjust the HDD size in HDtoolbox. In the latter case you should buy a new hdd and trash the old one. Before you do that your could try a full format or even a low-level format.
Bye,
Thomas
