Iso that work with discs might not work with usb loaders. I used to patch PAL games to NTSC with wiifrii and they work on discs but after transferring them to ext hdd they don't work anymore (black screen after pressing start). I had to unpatch them back to PAL in order for them to work.
Corrupted image is either cannot be view on your computer, or unable to display completely.
Alternatively you may use cfg loader. Unlike usb loader gx, it won't crash but the corrupted image will be abstracted instead.
It happens to me before too. Turns out that one of the boxart images is corrupted. Find out which is it by viewing the images from your pc and replace that image with a proper one.
Wii backup manager has issues with SSBB. Go to settings and change wii disc partition to keep to 'keep game partition only' and try transferring the iso again.
my wii is softmodded with 4.0 system menu. The patched disc can be loaded and played with no problems except for the lagged cutscenes. Recently I'd just bought a 1tb ext hdd for the usb loader, loaded the game with the hdd and it works perfectly! no more lagging cutscenes and games are now...
I have the exact same problem too! Burning the iso again doesn't solve it either. I'm pretty sure I'd follow the steps correctly to patch the english files in. Other than those cutscenes, the game seems to run pretty smoothly.
The copy with the unpatched iso works fine though.