Hi!
I do exactly the same on a system. Check out this guide and the solution is at the end of the text.
I think I discovered a bug here. Run NCS as a service on the source computer with the USB cam. Then you get both video and audio and two green dots when you do the test on the target computer. If you run NCS X on the source computer it will only connect using MJPEG on the target. Testning with MPEG4 will result in two red icons. I reported this to our developers.