Not showing any text in addons page or firebug (Lucida Grande)

Hi, I've been facing this weird issue with firefox fromt he past 2 days, the failure in rendering Lucida Grande font. Even when i open the Add-ons manager in firefox, only the images show up and no text. (Here, the font family for the page is Lucida Grande","Lucida Sans",Helvetica,Arial,sans-serif). However, when i change the font family to arial or any other fonts, its showing up the text. And because of this issue, I'm not able to use firebug also, (especially the computed css section. I guess they are using the same font in firebig too)for development. Any help with this would be appreciated.