duplicating a dvd video

[Dave]

Hello,
    I asked about this a while back and got some good feedback. The issue is 
it isn't happening.

    To recap i've got some family-made dvd videos that i've been asked to 
duplicate. They are quite lengthy and as i discovered won't fit on to a 
single layer dvd, so i got a three-pack, which i've already killed two, 
duel-layered dvds. My dvd writer can burn duel-layer dvds and the players 
can all play them so that's not an issue.
    What i did originally was to run dvdbackup on the original dvd video. I 
inserted it and ran:

dvdbackup -i /dev/cd1 -o /path/to/backup/area -M

which created a folder under there called video_ts. A segway i put in a 
movie in to the dvd drive, mounted it and checked it out that also has the 
video_ts folder so i'm sure that's what has to go on the dvd. I put in one 
of the blanks and do:

growisofs -Z /dev/cd1 -dvd-video /path/to/backup/area

    which upon mounting the resulting dvd i confirmed that it does have a 
video_ts folder on it. My issue is when i try to play them i'm getting disk 
read errors. The only thing i can think of is i have to make iso images 
first, but i'd like confirmation on this or an idea of what i've missed 
before i try this again, i'd really not like to burn another coaster.
Thanks.
Dave.