Eazy all you need to do is go to a consol and su to root
once your root type
pkgtool
you can rerun though the setup scripts in there.
but if your in a bind you can always go into the /dev directory and create a symlink to the com port used for the modem like thus
if modem was on com1 then
ln -s /dev/ttyS01 /dev/modem
See im not totaly useless here