This is the known issue. You can track issue at
https://github.com/detro/ghostdriver/issues/394
There is a workaround available.
Download source from phantomjs http://phantomjs.org/build.html and edit hub_register.js in the src/ghostdriver
comment out lines as shown below:
//var ghostdriver = ghostdriver || {};
  return {
    capabilities: [{
      browserName: "phantomjs",
      version: version,
      //platform: ghostdriver.system.os.name + '-' + ghostdriver.system.os.version + '-' + ghostdriver.system.os.architecture,
      maxInstances: 1,
      seleniumProtocol: "WebDriver"
compile and everything works!