Beginner level error: done is not defined

Hello,
I am a beginner in nodejs and require some help regarding the usage of yakbak. Hope, you don't mind :-)

Situation:
At present, I develop ASP.NET webmethods via Visual studio and manually test them. Once I start a visual studio project, the test url becomes: http://localhost/<random-but-valid-port-number>. This link can be opened via any web browser (e.g. chrome, firefox), for which I think node modules can use it also.

Code I tried:
I have started the visual studio project, and it has started on port 52280. Therefore, going to http://localhost/WebService1.asmx/Ping yields a valid timestamp (code written by me which I want to test). Code I have written in index.js:

// Contents of index.js
try {
    var yakbak = require('yakbak');
    var http = require('http');

    var validPort = 52280;

    var proxy = http.createServer(yakbak('http://api.example.com', {
        dirname: __dirname
    }));
    proxy.listen(validPort, done);

    var options = {
        host: 'http://localhost',
        port: validPort,
        path: '/WebService1.asmx/Ping'
    };

    http.get(options, function (resp) {
        resp.on('data', function (chunk) {
            console.log(chunk);
        });
    }).on("error", function (e) {
        console.log("Got error: " + e.message);
    });

} catch (e) {
    console.log(e.message);
    console.trace();
}

Example
If I try 'WebService1.asmx/Ping' then I would expect 2016-07-18T15:50:04.483+06:00 (current timestamp) as response and this response should be cached so that if I call this url later, then I will get the cached response instead of current timestamp.

Desired output
I want to control the variable options (i.e. path) and fetch response from that particular path. Then, I will compare the result in resp.on which will be same as the example output above. I expect yakbak to mock/cache the response.

Actual output

$ node index.js

done is not defined
Trace
    at Object.<anonymous> (C:\Test\index.js:28:13)
    at Module._compile (module.js:541:32)
    at Object.Module._extensions..js (module.js:550:10)
    at Module.load (module.js:456:32)
    at tryModuleLoad (module.js:415:12)
    at Function.Module._load (module.js:407:3)
    at Function.Module.runMain (module.js:575:10)
    at startup (node.js:159:18)
    at node.js:444:3

[nicu]

proxy.listen(validPort, done);

you are calling this function but it doesn't seem to be defined in your code.

You are right, afternoon bug :-(

However, I fixed the line and tried again. But got this error: listen EACCES 0.0.0.0:52280. So, I think yakbak's proxy (i.e. nodejs proxy) is not able to listen to the visual studio project's port.

Then, I wonder, how browsers are able to listen to that port?