Thank you.
I've now tried everything they suggested. I found that when I went in via Filters, I got more of the BRL box, but still not enough to get me to the OK. Unfortunately I couldn't get anything they suggested to work for me.
I know it's me, there's some incredibly obvious easy thing I'm supposed to be doing, but don't know about.
Edit: Well, I figured out how to get to that OK button.
Unfortunately, when I then actually
click that OK button, I get GIMP pop-up messages that say:
"Plug-in 'Bevel Reflect Logo..' left image undo in inconsistent state, closing open undo groups." and
"Error: Procedure execution of plug-in-map-object failed on invalid input arguments: Procedure 'plug-in-map-object' returned no return values"
Sigh.