I had a similar problem when I clicked "start" before enabling ticks, it should work just by clicking it once ticks are enabled in the "Simulate" menu in the toolbar.
I've labored on this enough to feel comfortable chalking this up to a side effect of using an edu tool from 2005, I'm sorry you are unable to be graced by this work of art and I wish you luck should you ever find yourself unlucky to use this program for literally anything. :/ <3
