Sometimes when my shortcut isn't working, I reset the key it is associated with in the other file or in game. So, though you can just the shortcut button in game, are you constantly hitting Shift-9 or whatever 21 is linked too, and it isn't working there, or have you tried both. I never use the button GUI for shortcuts anymore, just the keyboard keys, so thought I'd ask. Double check your keyboard shortcut for 21 and maybe reassociate to another key combo. I've messed that up a couple times. Yours does look fine to me, though, and yep, digging for cats or gold, you should at least get the same error message.
I'm thinking a nice little add on the top would be /dequip righthand, /equip Rock Pick (or Master Crafter Rock Pick) on the top, too. That way you know you have the proper tool going, though I think you'd get the error, "you must have the correct tool equipped" if the shortcut is even being activated. Maybe copy this code to a free shortcut button and try it from scratch, too.
