Pioneer DVD-RW DVR107D won't play back re-writable DVDs un..

Hi,

I can burn data DVDs with the Pioneer drive under Linux and Windows XP.
I can also play DVD movies under Linux and Windows XP (I use mplayer
under Linux). However, when I make a copy of one of my DVD movies and
play it back, it won't play back the movie under Linux (the original
movie does however). Also, the recorded movie will play on the DVD
player connected to my television.

The error I get from mplayer is:
libdvdread: Could not open device with libdvdcss.
libdvdread: Can't open /dev/dvd for reading
Couldn't open DVD device: /dev/dvd

The error in /var/log/messages is:
Jul 5 05:42:10 fender kernel: sr0: CDROM (ioctl) reports ILLEGAL
REQUEST.

The line in /etc/fstab for the drive is:
/dev/dvd /mnt/dvd udf,iso9660 noauto,owner,kudzu,ro 0 0

I've been googling for the last couple of days and found nothing
relating to the situation where this only happens with recorded DVD
movies. Any advise on fixing this or where to search for further info is
much appreciated.

--
Steve Webster