[Bushwick2002]

1. is it good to save the files as *.iso or *.gcm? dont matter, its the same format just different extensions.
2. should i not have anything running in the background while doing it? you could run things in the background, it shouldnt slow it down or speed it up.

some error popped up in german when i tried and it piled ontop of one and other :S not sure what error you mean. If you mean hiting "Shutdown Server" button then its normal for a popup error to come up after it finish backing up a game.