Seems like FF4 is not compatible with Google Fonts.
FF4 does not display Google fonts by default. Just test it : go to http://www.google.com/webfonts/preview#font-family=Allerta+Stencil and then in another browser. Don't really wanna change anything in the options as most ppl won't be aware of this bug and just see website with the wrong fonts. :(
Todas as respostas (1)
Is this pref still enabled: gfx.downloadable_fonts.enabled -> true
To open the about:config page, type about:config in the location (address) bar and press the "Enter" key, just like you type the url of a website to open a website.
If you see a warning then you can confirm that you want to access that page.