MUDFLAPPER  I don't think it's the app. Sounds like you have a corrupt font.  
(Version 1.2.3)

MYSHKIN2  An application shouldn't crash and lock up the whole system because of one corrupt font. i.e. it's a rubbish application  
(Version 1.2.3)

MUDFLAPPER  Actually, fonts are notorious for crashing EVERYTHING. I used to have so many problems with corrupt fonts causing every app that used them to crash.

Font Explorer is the most reliable, trouble-free font app for the Mac. Trust me. It's not the app causing the problems.

Make sure you have deleted all other font app plugins. Use something like Font Doctor to diagnose and fix/remove corrupt fonts. Clean the all font caches using Font Explorer. Restart. If it was a font causing the problem, the problem will be gone. If it's still there, there is something wrong with your system.  
(Version 1.2.3)

MYSHKIN2  Actually Suitcase is much better as it tells you whether a font is corrupt and offers to fix it and doesn't just lock up and crash your system.  
(Version 1.2.3)

MUDFLAPPER  FontExplorer does that too, but sometimes, if the font in question is a system font, or a font used by Microsoft Office apps (for example) stuff starts crashing before a font manager gets a chance to warn you.

It's a real pain in the ass. I had so many issues with Quark and bad fonts a couple years ago at work. And, of course, it only seemed to happen when there was a nearly-impossible-to-meet deadline. Ugh, bad times.  
(Version 1.2.3)