Problem solved. It turns out someone at my former LBS must have lost that threaded insert and decided to drill out the hole and tap it for a larger bolt. They also drilled out the little metal piece that clamps the cable down. I had to find a bolt that was the original size, grind down a nut so it would fit in that recess, and use a washer to compensate for the larger hole. If they were still around, I'd have all kinds of nasty things to say about that shop and why I'm never going back. But, they had to sell the shop a while back because they got caught selling stolen bikes. Obviously those guys weren't too bright.
Thanks for the help!