Some installed fonts do not work properly

[Guest Sadeq]

Although my XP have italic variants of Arial and Times fonts installed, some programs do not recognize them, see for example the following images (An error message from "American Heritage Talking Dictionary" software):

I checked my C:\Windows\Fonts folder. I have: ariali.ttf, arialbi.tff, timesi.ttf, and timesbi.ttf (corresponding to "Arial Italic", "Arial Bold Italic", "Times New Roman Italic", and "Times New Roman Bold Italic" respectively) all in place.

I'm confused. Why programs such as MathType, American Heritage Talking Dictionary, and so on do NOT recognize these fonts, while programs such as Microsoft Word DO?