Comment by pekka.klarck:
@tuomas.kajosaari This demo uses Firefox by default. Do you have it
installed? Selenium also sometimes fails to use browsers out-of-the-box. If
you are just interested to try Robot Framework and SeleniumLibrary out, I
would recommend you to try some other browser. Otherwise you can try to see
if you find any more information about the failure from selenium-server.log
file (I'm not exactly sure about the file name) or elsewhere.
For more information:
http://code.google.com/p/robotframework-seleniumlibrary/wiki/Demo