as far as i searched the net, i got 2 things. take this as the last option, which is to replace ur drive hoping it has a problem in reading the double layered dvds.
the option for u to try out is they say "firmware updation". a
link is here.. where similar problems are discussed. see the last reply for the solution he mentioned. u can google to get a firmware update for ur drive. one such is
here amnt sure if its available for ur device here. and u hav to make sure if this is the problem. i hav just found out this may be an issue. and also carefully read the instructions for updating it incase u feel its the prbs. GL.
/legolas