no idea...I have this same problem with the new fluxbox devel version (and cvs too)...tell if you know
I think it's also a part of this problem that my Firefox keeps on telling it's not the default browser (even if I set it to be), if I don't uncheck the option in it's prefences that stops that...fluxbox doesn't seem to save these things or something.
yes, an enlightening post about this would be very nice..