Mozilla Firefox 4 has made it's way to the final release, and while most of the addons are compatible with the new update few still needs updation. There could be two reasons for an addon not to work with Firefox 4 - the first being it got functionally broken because of the new changes made in Firefox 4 (very rare), and secondly the developer has not yet updated/declared the addon to support the updated firefox version. Luckily, we have a fix for the second problem as shown below.

To get the addons working, follow any one of the two solutions :