Both these replies are a bit rude and unhelpful. I am editing in Premiere, and I am not very familiar with it. The question is about how to fix lens distortion in Premiere. Maybe there's a way to do this that I'm not aware of...? That's why I asked the question! There's nothing about it that I could find in the forums. The only fix I found didn't work—which was to use Photoshop *integrated with Premiere*. And two people tell me to use AEFX without pointing me in any directions of how to do that. Useless.
Anyway, I found some information that *was* helpful. This tutorial demonstrates that one critical step was missing from the prior tutorial, which is to convert the video layer to a smart object before applying the effect:
The same person provided a tutorial on how to do this in AEFX:
Now that these steps are taken, I have to take the footage back into Premiere. It's a workflow question. Other video editing software has this kind of stuff built-in to the effects panel.