I set up a browser automation project using Selenium WebDriver. It works just fine. When I try to run it on an other machine, though, it opens the browser (Firefox), but that's it, no automation. When timed out, it throws an error: "Failed to start up socket within 45000 ms. Attempted to connect to the following addresses: 127.0.0.1:7055". 7055 is the default port the firefox driver attempts to use for communication (see this article).
On my machine, where everything works, Firefox has an extension installed called "Firefox WebDriver 2.42.0". When I type 127.0.0.1:7055 into the browser, it opens a page titled "httpd.js". I suppose it is served by the extension, because on the other machine it's not opening.
I was unable to find the extension in the web for download, and I was unable to understand where it comes from - it apears to not be installed manually.
Please help.
edit: reworded the question
I was able to solve the problem. I was trying to run selenium 2.42.0 with firefox 38, wich is not supported. i updated both firefox and selenium and now everything works just fine again! :)
See this for more details about compability.