Missing fonts?

[Mugen]

Well it seems like whenever I try to browse sites on Firefox, or certain websites on Safari I will get a bunch of symbols as opposed to words.

http://img261.imageshack.us/img261/646/borkenie6.jpg

Is an example. Also, when I use AIM certain fonts just won't be recognized.

 

[Natobasso]

Make sure you have all fonts installed in your system/fonts folder.

Apple's support doc on font locations:
http://docs.info.apple.com/article.html?artnum=106417

The list of system fonts required to run Mac OS X:
http://docs.info.apple.com/article.html?artnum=25710

Also, make sure your browser isn't using a font you chose that isn't loaded in your system.

Are you using FontBook or another font management program?