First, thank you for the response!
I can click on it in Forms Edit with no problem, but it can't be deleted. I click on the field and it is highlighted in blue to show I have it selected, and I can then PICK "Delete" and click on it, but it doesn't do anything; the blue highlight goes away, but the field is still there. If I'm not in Forms Edit mode (if I'm just in Content Editing), I can't even see it. It's not set to hidden, locked, or anything like that. Like I said, I wouldn't care if it was there or not, since it won't be visible to the end user, but it seems to prevent me from making the form submittable.
I would attach the PDF for review if that would help, but it doesn't look like I can do that. I've never used the Adobe forums before, so maybe I'm just not seeing it.