Need some help...

 From:  Rudy
2354.1 
Hello all,
I would like to fillet the edge of my jewelry band (see pic 1) and I do that by highlighting the two edges, and input a radius of, let's say 0.5mm (see pic 2).
I have two files...they are basically the same design, except one I did it with a scaling rail.
The one with a scailing rail can do the fillet no problem.
The other file, cannot fillet the edge.

Do not understand. What am I doing wrong?
Any help out there,
Thank you,
Rudy