Region Code won't change even with 1 change left, how come?

I just inserted a new dvd into my macbook and the region code changer popped up. It reads: This is the last time you can change the drive region. And that's cool, the new disc is my normal region - except when I do change it in the dialog box and set my last and final region - dvd player just quits itself.

When I re open it, the region code changer appears and it happens all over again.

I've tried re-booting and trying different discs but nothing works. I'm not even getting an error message.

Can anyone help me?