Maybe you need an updated version of Roboform. Have you checked to see if there is one? It's not uncommon to have plugins stop working when new versions of browsers come out.
I recently upgraded Firefox 21 to Firefox 22.
When Firefox restarted everything about Roboform was gone and it was no longer working.
I went back to Firefox 21 from my bak up and now Roboform is working normaly.
How do I get Roboform to work with Firefox 22??