Disk Utility Restore causes "Could not validate resource - Invalid Argument"

I would suggest WinClone, which worked well for me once when I needed to backup a Bootcamp partition. The developer's website is here: http://www.twocanoes.com/winclone/

You can try an older, shareware demo here: http://mac.softpedia.com/progDownload/Winclone-Download-27227.html The third Download Location labeled as "Softpedia Secure Download (RO) [DMG]" appears to be still available.