We should boycott this site! All the NES manuals are stolen from
http://www.nesfiles.com and from other sites. The only work they actually did is to add their own banner to the first page of the manual and to encrypt the file so no one can ever modify the PDF again...
If you want NES manuals, go to
http://www.nesfiles.com and download the unmodified ones. But please don't support these lamers!