Thank you for this info! I have learned, that version 1.0.0.1 is installed on my system, which is the most recent and stable version of libdv.
The bug is only in Kino, with which i made the screenshot. So there is nothing to worry about here in synfig.
EDIT: Now, that i have updated my system to Xubuntu 8.10, i see that encodedv --version in a console gives me :
encode: version CVS 01/14/2001, libdv.sourceforge.net/
Is this a very old one? does it have this bug still, or better not yet?