3520a in QUE Fire case

g-day I bought a internal dvd writer and put it in an old cd burner external firwire case
all burning applications see it as a dvd burner but it only burns cds (without a problem)
when I try burn a dvd it starts and says “writing lead-in” and thats where it stops when I take out the dvd its only burnt about 2mm
any help would be apreciated
iMac 450
512 ram

iMac ? Maybe a bug in the OS… or poor driver support.