After developing a new feature for this site and testing it, I uploaded it to the production server but kept getting this error:
Error: The requested address "..." was not found on this server
After double-checking the CakePHP core config and routes files and that I had added the new database table to the production server, I couldn't figure out why the page was still displaying this error.
I did a bit of googling and found out that I had to clear the /tmp directory of all files and folders. I did this and now it all works. Thanks to the DevAyd Blog.