It is the other way actually. It is not uncommon for the Roboform toolbar to need to be updated for every new Major release however thankfully they do not do the need to update toolbar for every little minor update patch like they did in past and drove Rf users nuts.

Actually the Roboform extension should work on Firefox 4.0 if you have the recent version though it is not problems free.

So.....would you advise giving 4.0 a try with an update of Roboform?