Firefox and Fontello Icon Issues

The Minicorp icons are don’t work in firefox. What can I do to fix this? I’ve read several things about it; that adding the fontello_embedded.css file to my site would fix it and that adding something to my .htaccess file would fix it. I tried to latter option but it didn’t work. I’m not sure where to get the fontello_embedded.css file or if that is even the solution. Thanks for your help,