hi all and thank you for this great forum!!
now here's the problem:

i have some movies on -r dvd's that work perfectly on mij jvc standalone dvd player,also +r dvd's work on my standalone player.
When i rip and burn óriginal dvd's on +r dvd's they work fine on my dvd player.
but when i copy a -r dvd straight to a + r dvd it won't play on different standalone players.
i copy the -r dvd's with copytodvd
my burner is a plextor px-504a

what could be the problem,should i use another dvd copy software??
please help!!