Hi xor
You do not make it clear what it is you are trying to accomplish.
If you are trying to make sda5 a duplicate of sda1 , then remove the /image.iso from the command.
If you are trying to make an ISO file for burning CDs, calling it .iso won't make that happen.
Maybe you want to Google mkisofs for creating an ISO ? It's provided by cdrtools.tcz.