jsonRPCClient.php states its served a 401 error response
I think this is related to this open issue. 

https://github.com/bitcoin/bitcoin/issues/9661

I was running bitcoind on Ubuntu 16.

I had the similar issue when I had rpcuser and rpcpassword in the config file. All I got is 401 error when I called the jaon-rpc api.

I found a workaround by providing -rpcuser=REPLACED -rpcpassword=REPLACED when I launched the bitcoind.

Hope this is useful.

One more thing, instead of debug from your rpc client in PHP. Maybe try it with curl first. HTTP 401 clearly is an authentication issue, using curl is much easier for debugging.