Friend cant see my webcam

hello i recently got the new yahoo messenger and have a webcam. i broadcast my webcam but my friend cant see it - i dont know why. the webcam icon is disabled and the option of "invite contact to view your webcam" is disabled. does anybody know why this is? its a microsoft webcam I have yahoo messenger and a microsoft webcam. My friend has a mac integrated webcam. He can see my webcam, but when he invites me to see his all is see is the box where his image should be and there is an advertisement in it.