I'm not entirely sure if this is the correct way to do the computation
but I see no other way of fixing it but since the zero vector is a valid
value for the relative velocity this seems to be the most sensible
solution.
Also, related to this I found out that FSO causes a lot of NaN errors at
runtime which may need to be investigated at some point to make sure
they don't cause issues like this bug.
If the -noninteractive command line option is set then dialogs won't be
shown and the default action is taken. This should be useful for
the standalone server.
asarium