Messiah V5 Not Reading DVDR's

[typhoon]

Can anyone help i have had a messiah V5
fitted but have not been able to play DVDR's.
also i have tried many types of disks cheap to expensive
but no joy is there something im not doing right ???
The machine runs cdr's with no probs at all and norm game and
film dvd's and have tried different ways to load the games ie
reset button x1 & X2 cold starts etc all hints and tips
will be greatfully recevied