Good that you got it to work!
The connector (together with the gateway) provides HTTP connectivity to the mobile from the Internet. But, in addition to that, the only thing the connector does is to forward the HTTP request to port 80 (or some other port if you have change the settings). If nobody is listening on that port, you will see that Internal I/O error.
Start, for instance, MWS in local mode. Or actually, it does not matter even if it connects to the MWS gateway as well. You will still be able to access it via your gateway.