I know this is an old post but since I dealt with the same problem today I send my solution the same. In my case the problem was caused by a missing library: libdvdcss. If you don't have it you probably have to activate the medibuntu repository. The message given by the program is not clear at all anyway. Hope this helps someone.
-- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/445864 Title: Impossible to open a *.iso file To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/k9copy/+bug/445864/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
