Reinhard:
You are a genius! Mystery solved. Your question triggered a moment of illumination in my mind.
I tried out some firewall software and I didn't like it because it was blocking legitimate users from my site. I deleted it. I did not know that before I deleted it, it added an .htaccess file to my uploads directory, blocking all php files from executing. Deleting that file restored the sunplot to it's original function.
Once again you have saved the day.
I love this little script Mark wrote and am glad I can still use it.
Thank you, mate!