dunno its weird, happend to my mate kinda
i got a dvd region x, so has he, i took my cky seires ( region1) over to my mates, and as my mate live round the corner, i used my dvd region x on it, wouldnt work......, so went back to his, got it, used his and it worked...
so maybe when you have used it once, it get burnt on the card part ( mine has a bit you have to put in memory card slot.... my mates doesnot) so buy a new dvd region x and try it... if it works put the old one back in the box and take it back......