I didn't know any projectors shipped with ANY cables.
I would head over to
www.bluejeanscable.com and pick up a 30 foot s-video cable.
EDIT: Why are you hooking up s-video anyway? About the only thing that uses that are S-VHS players and camcorders...
Your PC should be VGA, your DVD and HD cable/sat box should (must) be component or better.
Otherwise, I'd just add a composite cable so I can have my on screen menu for my A/V receiver and to see my security cameras.