Editing VOB files which are the mpeg2 files named in the dvd styles convention ( and which you can rename Mpg) files is generally a bit of a pain but is possible even with S9. The FAQ method encorages a means to turn them back into AVI which are less of a hassle to edit.
I do worry though about the usability of S9 ( works for me but Im told im in the minority)
You could try Downloading a trial version of Adobe Premiere Elements 2 and see if you can edit you dvd files (ie vob) with less worries of suspect stability
http://softwareupdates.adobe.com/upd...l.jsp?cid=2674