I am so confused @__@ Alright if you're trying to install the game via USB Loader GX's "Install" option then just insert the disc then play it, I did it with mine and it worked (the download speed is outrageous 3 mb/s WTF, took me 15 min to download brawl o.O). If you're trying to play the backup then make sure you have all default settings and have rev 14 or rev 17 (there's controversy between rev 15, rev 16 and people say they have no problems but I got with majority so just trust me on that ;D).
Still re-reading everything, I still don't get wtf you're saying lolz, what I said above is based on your first post and nothing else. Pardon me if I answered it incorrectly.
Hope I helped ^^