Trusteer Rapport have made a version for Firefox 4, to get it go to http://www.trusteer.com/support and type in "Firefox 4" as the support question.

hi TonyE thanks for the help.after i posted the problem,i decided to uninstall rapport & download it again via my hsbc internet banking account(which is where i first found out about rapport) while i was logged in via ff4 rather than iexplorer.worked a treat!!.looks like you were right about the ff4 version cheers isseyman.