Also, I was having a similar problem, fixed my region code, still no luck.
I tried running /usr/pluto/bin/disk_copy manually and pointed it at /tmp to put the file in. that worked. I poked around /var/log/pluto/DCERouter.log. I eventually discovered that i was getting an error when it tried to open /mnt/device/122/public/data/videos as that directory didn't exist yet. Now, ripping a CD automatically created the audio directory so i'm not sure why ripping a DVD doesn't do the same; however I went and created the videos directory from the command line and tried ripping the DVD again adn its working.