It is probably a problem on my machine (Mac OSX 10.5), but if I use Arial as a font, I get incomplete rendering of strings. Text with fontWeight set to normal renders okay, but it only renders a few characters when fontWeight is set to bold.
global {
fontFamily: Arial;
}
It will only show the characters ‘aegknrsvw’. If I use Verdana, there is no problem.
Update 24 feb 2010:
I found out what caused the problem. In our Flash preloader, we embed some Arial characters:

And these embedded characters were exactly the only characters that were rendered correctly by the application. Once I removed the embedded characters, everything worked fine.