help with disc errors, newbie,

ok so im still learning all this, but i catch on quick.
i have homebrew up and running, dvd playback works, emus work fine.
problem im having is with reading dvdrs for backups.
i burn the iso using imgburn, then put in my wii.
the will loads up with the safety screen, but after that is goes black and i get disk error, cannot read disk check wii owners manual.
im getting the iso from piratebay, burning then with imgburn.
using dvd+r optimum.
is their something im missing or not doing right ?
thanks all.

This should help:

http://forum.wiibrew.org/read.php?1,6510

actually i dl a few more isos, and i get them to start working, 4 min into playing all of them they either freeze up or screen goes black, and have to reboot, its driving me nuts, whoevers a pro at this and wants to help guide me through whatever im doing wrong, write me on yahoo messanger, screen name is foreveraudio