Adobe Illustrator won't read TrueType?

I’ve had a .ttf installed for a long time and Illustrator CS4 won’t let me use it. It doesn’t show up in the font list, but if I start typing it, it’ll appear. Once I hit enter, though, the text reverts back to whatever font it was previously. I converted it to OpenType just to see if that helped and it didn’t. What gives?

Also: Photoshop can render the font just fine in both .ttf and .ot1.