When i start PD and then plug webcam, it's killing pd.
I have tried another way, I plug webcam first and then start pd, I got same result
What's the problem?
I'm doing something wrong?

with a patch? then i'd say that's the problem. platform, version?

i ran different webcams on mac and linux and never had a problem.
in case your cam is the problem, think about the ps3 eye
http://createdigitalmotion.com/2009/08/06/trick-out-your-ps3-eye-webcam-best-cam-for-vision-augmented-reality/

Yes, with a patch
I m running on windows XP and I have some shitty Genius webcam

i guess you already tried the 14.live_video.pd help file?! if this doesn't work as well, i guess i can't help, sorry.