I'm not sure where you're seeing this final size estimate, but a good rule of thumb is that you can fit about 70 minutes of video on a single-sided DVD before the program must reduce the quality to fit it.
I can't imagine you can fit a 160 minute video in 2 gigs of space.
In PRE8, after I click "Share", I choose "Disc". If I choose the folder option, then un-tick the "Fit Contents to available space" button, it shows how much space you need without altering quality.
Any thoughts why it would say 2GB for such a long DVD? I think this may be a clue as to why it's crashing during the encoding, that's why I'm asking.
Presumably you have the slider set to the leftmost position. Leave "Fit Contents to available space" checked and it should work OK.
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