Font display issue (Mac OS X)?

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http://serverfault.com – I used a font manager on Mac OS X, for additional fonts in my graphic design projects without installing them to the fonts folder (I think that's how it works) - using Font Book and Font Explorer X Version 1.2.3 on OS X 10.6. Most fonts work fine, but Interstate has a problem: Interstate Regular is installed, but for some reason it's probably not seeing it; it's seeing all the Bold and Condensed versions fine. In the above image, it displays the second font as Interstate Regular, but it isn't that font... why? Also, how do I reset the system fonts folder back to the default-installed fonts (HowTos)