Unity/FaceAPI integration: Object reference not set to an instance of an object

Hi everyone,

I'm trying to integrate FaceAPI with Unity following this example: http://issuu.com/sriramdasty7/docs/unity_3d_faceapi_integration

I created the script (named it FaceAPI) and attached it to a Main Camera. But when I run it, I keep getting a NullReferenceException: Object reference not set to an instance of an object

Apparently, he's not agreeing with this line of code:

 byte[] receive_byte_array = listener.Receive(ref groupEP);

Can someone please help me with this? Thx in advance