Thanks so much for all the suggestions and info. I took her to 'school' last night and she was as perfect as she has ever been (without the clicker). In fact, the trainer asked me if I'd traded her in on a new dog. We have decided to just forget about the clicker training. As long as she works that well, we'll keep using treats and praise alone.

Now, I just have to get her to trust me again in the house so that she'll accept treats from me (that shouldn't take too long, as long as the dreaded click doesn't reappear). I'll keep the clicker, though, and try it whenever I get a new puppy, which will not be anytime in the near future.