Creating DVD problem

I can't create dvd by dvdauthor, and I do not understand why. The error
output does not give me real information, I can understand.

The example .xml I've taken from here:
http://dvdauthor.sourceforge.net/doc/ex-title.html

<dvdauthor>
    <vmgm />
    <titleset>
        <titles>
            <pgc>
                <vob file="vob_02t_001.orig.vob" />
            </pgc>
        </titles>
    </titleset>
</dvdauthor>


When I try to create dvd from file from .vob created by dvdunauthor I
get: 

ERR: dvd info packet is version 1


when I try to create dvd from file modified by ffmpeg (I've added new
soundtrack to the file I've wrote above) it gives a lot of:

WARN: Skipping sector, waiting for first VOBU...


Both error messages does not explain what is the matter, and how to fix
it. Googling does not give any use too...
Can somebody tell me what to do? ;-)

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