xwave LB900

[scouseman]

i own a xwave lb900 plays all dvd films vcds mp3 etc but wont
play dvdr discs ....my firmware is
version2.5171
sub version v1.00
tv encoder adv7170
dvdloader is dsl-600a
region id is 0

my friends machine is the same above and plays dvdr discs
but mine wont ....does anyone have any info on this ?
thanks