<?php
phpinfo();
open it in your browser and look for output_buffering.
This worked for me. When I looked for output_buffering it was indeed set to a number. I did a search in my php.ini and found that in one area I had it commented out with the default value being off. But when I searched further I saw that output_buffering was set to 4096 further down in my php.ini. I think I did this before, but forgot about it. Once I commented out the line, the error was gone.
So the moral of the story is that I had two different output_buffering settings in my php.ini
Also make sure your editing the correct php.ini. At the top of the phpinfo.php web page is what the file location of the correct php.ini in use is.