If it appears that the keystroke isn't working, it may be coming too quickly. You can add
Pause between
LRCopy and
Key1. That adds a 0.02 second pause. If that's not enough, keep on adding Pauses until it works. Do make sure that Lightroom is the foreground application when doing this, as, on a Windows machine, MIDI2LR is sending keystrokes to the foreground window (on a Mac, it sends to Lightroom regardless).