In IE 8.6007.18702, the arrow next to the username shows as a DLE type block. In Firefox it shows correctly as an arrow.
UPDATE: I have the font that Jeff references below, and the issue still exists. So it's not my OS nor lack of fonts. I am using Office 2003. Perhaps the arrow should be changed to an image instead of a 17 pixel font character that may or may not be recognized. On Vista Home Premium using Firefox, the character is not shown at all.
EDIT: Image from Firefox 6.0.2: