matshita drives seem to always be a special circumstance. I'm no tsure of the specifics, but if you do a search for matshita on this forum you'll see what i'm talking about.
there's something about the hardware that keeps anydvd (or ANY software program) from effectively emulating whatever region it's supposed to be emulating (which is probably how the original poster ran out of region changes in the first place...it kept asking him to switch since software can't do its job)
i think you may be stuck since it's a hardware specific issue that can't be solved by software means.
like i said, i've never owned a matshita drive so a search on this forum might be more enlightening.