Dear Jeffrey Lash, have you tried it in another time once again? I have tested it several times, and it works for me. Try to open the URL you mentioned - http://cityengine.esri.com/ce_projects/projects.properties.php in web browser. Does it returns something?
If not, try to run Fiddler - Free Web Debugging Proxy - Telerik tool alongside City Engine to catch the network communication. Maybe there will be the answer.
Have a great day.