Trying to use Codeception Web Driver and Selenium to emulate ajax through an acceptance test. I was using PhpBrowser but when I was having issues with Ajax my friend suggest
I had the same problem, with the exact same error message. For some strange reason, it looked like starting the selenium server from command line did not work.
My solution turned out to be manually opening the selenium server through Windows Explorer, right click on the file, choose Open with -> Java Platform SE Binary.
Took me almost 3 hours to figure it out, so I hope this helps somebody.