Problems with Safety Minder, MacOS, and Firefox 4

I bought a new Mac laptop this week.  It is running MacOS 10.6.  I downloaded the lastest version of Safety Minder and installed it.   I confirmed that it is functioning properly with Safari.  However, when I install Firefox 4, none of the restrictions are applied.  You can browse anywhere you like.  Is there some setting I missed or is this a known bug?  I haven't even tried it with Chrome.  Can someone please help?