Web cam works fine. But Yahoo says it is being blocked by firewall. But I enabled Yahoo messenger and the cam as exceptions. No luck. Vimicro 301 cam. Any ides as to how to enable cam on Yahoo Messenger? Thanks.

You may encounter this problem when both webcam participants are behind firewalls. At least one needs to have the ability to accept incoming connections. (Skype is the only voice/cam app I've seen that is consistently able to work through firewalls)

If you're on a network, your router may be acting as a hardware firewall. Consult the documentation that came with the router for instructions on how to open ports. (I don't recall which series of ports YIM needs, check YIM help or your PC's firewall may also be able to tell you)