During an upgrade from Fedora 15 to 17, I installed into an existing LUKS encrypted partition. I'm sure I borked the boot loader options, because the new system boots to GRUB. When I attempt to fix the problems from the boot cd and run
cryptsetup luksOpen /dev/sda3 cryptLVM, I get that error.
I read about header problems and the cryptsetup man page lists a "metadata repair" option for "benign" problems. I don't know what the trouble is and looking for the simplest answer. And yeah, I backed up (^_^)