Hi, I've just got my first imac so please excuse me if this is a silly question. I've got a dmg file that I wish to open from a dvd. I've double clicked on the .dmg file's icon in Finder and I have a dialogue box open that says that it's opening the .dmg file in question, and that it's verifying it. However, about a third of the way through it tells me "The following disk images failed to mount..." and that the reason is an input/output error. Does anybody have any ideas as to why it's doing this? I've tried another .dmg file from another dvd and it does the same thing at about the same point in the process. Any help would be very gratefully received.