Password Prompt Font Problems

I installed the Fontcase demo onto my intel iMac running Snow Leopard. Afterwards I noticed that font on the system password prompt had turned into symbols. Each letter now just appears as a box with a capital A inside it.

Here’s what I see when asked for my (user) password:
http://img208.imageshack.us/img208/374/passwordfont.png

I uninstalled the demo, but the problem persisted.

Has anyone encountered this problem before? Or can you tell me what font the password prompt uses so I can find it/reinstall it?

Thanks