Updates:
Status: Invalid
Comment #1 on issue 878 by pekka.klarck: How to execute firefox 4 from
pybot?
http://code.google.com/p/robotframework/issues/detail?id=878
Robot Framework itself knows nothing about browsers so this issue is
invalid in Robot's issue tracker. If you are using SeleniumLibrary, issues
related to it should be submitted into its own tracker. Questions like this
should, however, be sent to the mailing list and you should also give more
information about your setup for anyone to be able to help you.