Click inside the Reminders window, then click the File button on the top bar, and then click the New button in that drop-down menu. As soon as you make the reminder, the dialogue should advance. :)
Oh, I figured it out eventually - I always do. It just takes me a while sometimes to see the plainly obvious. Just finished the game a few minutes ago.
I really appreciate all your help! And I appreciate your taking the time to reply to my earlier comment, too.