As Firefox users are probably aware, not all sites work 100% correctly in Firefox. You can typically get around this in a few ways, so here is another method to add to your toolbox.
The User Agent Switcher Firefox add-on allows you change the way Firefox reports itself to a website. For example, you can set the User Agent Switcher to make Firefox report itself to websites as IE. This way the web page will send information to your browser as though it were IE and not Firefox.