Hi Pablo,
Yes it looks like your dvd reader is b0rked. Can be also the dvd scratched or an error at burning.
To create a live usb from another gnu/linux system is easy using the install-usb-live script inside the Sdk code repo. Gimme some time and I'll document that.

Thanks people for the translation! I think especially the part of food systems is important to.. expand our consciousness ;^)

Ciao