It looks like you found the game object with that name, but not the script.
You probably want:
plyrHmn.GetComponent<plyrHmn>().plyrFunction()
I would suggest that you try to use a public variable or private with the SerializeField attribute, and drag n drop the reference in the inspector, as opposed to using GameObject.Find which is slow and error-prone.
quick edit to echo @Brathnann 's suggestion for adding the OnClick event in the inspector, if possible.
Check out this thread for how to post code directly into the thread, nicely formatted, so you can avoid screenshots of code in the future: Using code tags properly