if I'm not mistaking, you're starting a GUI app (probably X-based) every X number of seconds... not quite handy unless that's exactly what you need. If you're not in front of your comp every X seconds, you'll end up closing Y number of app windows :)
In Re: Webcam 0.2 I use cqcam which is a command line tool.

Greetz
Beatnik
... Quidquid perl dictum sit, altum viditur.