Ctrl-A on both before typing in the BevOb. (also call your Curve “Rail” and your Curve.001 “Shape” or “Profile” or sumsuch to make it easier for all of us to see from your pics what you’ve done).
You’re supposed to select the Rail and type in the name of the Curve that will be the “shape” into its BevOb field. I can’t see from any of your pics if you’ve done it that way round or got them farce about ace.