It would also be good to know if the meters are moving for whatever input source you selected. The first time I was setting ProScan up, I was going crazy because I could see the meters moving as if sound was being received, but I wasn't hearing anything. I somehow failed to notice step #3 in the instructions:
This would be if you're trying to listen on the same computer you have ProScan running on. If the meters are moving, you're getting audio. Just have to setup the output (loopback, webserver, etc.).