Well Russ, I'll give you the same answer that you got when you asked
the same question in rec.food.sourdough.
Carl's has a very high success rate, and almost always works. When
it doesn't work, the usual reason is that the person having problems
let the starter sit around too long before they tried to revive
it. Still, other stuff can happen too.
In your shoes, I'd send off for another Carl's, or try Mr. Baker's
sourdough starter. Also good is the King Arthur starter. I would
avoid, at all costs, the Goldrush starter.
Mike