I couldn't open my QuickCam on Yahoo Messenger.

I just bought a QuickCam Deluxe for Notebooks and installed it to my Windows vista business. I could use the webcam on Skype & Windows live messenger, but I couldn't use it on Yahoo Messenger.
Everytime I invited someone to see my webcam, it always said "you do not have permission to view this webcam" or "this person's webcam is not available", and sometimes the webcam was on but it's dark. I've tried to reboot it and reinstalled it, but I still have the same problem.
Now, my questions are:
1. Is there any better solution to fix the webcam so I can use it on Yahoo Messenger? (More solutions are better)
2. How to save the webcam on the computer without inserting the CD everytime I use it?
3. When I used Skype video call at night time, the cam is a bit darker even the lights were on. Why is this happening? And please explain to me how to set the Rightlight.
I would appriciate any answers in details.
Thank you,
Cheers