What could be checked first is that the connection is working between the device and the machine you are running the tests with.
What do you see if you try to access the URL with your Web browser? Depending a bit how your browser renders "HTTP/1.1 501 Not Implemented"-response, you should see
rather than a timeout, for example.
If the connection is working correctly, here is what curl should print when run on the machine you are running the tests with:
$ curl http://<ip-of-the-windows-phone-device>:8080
Sorry, not implemented yet.