This can occur on Intel® WiDi-capable Windows 7 and 8 devices using the Intel® WiDi software application. You will need to allow or "whitelist" the following software application in your antivirus software's firewall settings:
WiDiapp.exe – This is the Intel WiDi application used to connect to ScreenBeam. By default, it is installed in c:\Program Files\Intel Corporation\Intel WiDi.
Consult your security software application user guide for information on how to allow software applications through the firewall.