I am trying to build Selenium from sources but some of my tests are failing and the Owner of the project commented the following: I'd also suggest running the tests with Xvfb / Xvnc and '''making sure that you have a vanilla Firefox (as opposed to Iceweasel that ships with debian,''' I am not sure what Ubuntu ships). If you still get this error, let me know. I am using firefox bundled with the Ubuntu 10.10.. Could you tell me how to get the vanilla firefox in ubuntu..thanks in advance..