There's a bigger thread here
on this issue. (If a moderator is reading this, I recommend merging the threads or closing this one down to avoid duplication.)
I haven't yet tried Mint 14, but based on what I've read, it appears that its installer's EFI support leaves a lot to be desired. The thread to which I linked included Boot Info Script output from two users who had two very different problems despite the same symptoms. See my long post there for details.
Switching to MBR and a BIOS-mode boot is a practical option for many users, but this creates a lot of complications if the computer is already booting another OS in EFI mode. In such cases, doing a native EFI-mode installation is the best solution; but if the Mint installer is throwing fits over that, it creates a mess. The easiest solution in such a case is likely to be to try another distribution. In my experience, Fedora 17 has pretty good EFI support, so it may work better -- but even it isn't perfect.
Unfortunately, the transition from BIOS to EFI is proving to be a very bumpy one, for numerous reasons.