I had a small issue with ProjectPier.  I downloaded the ISO file and installed it on a local virtual machine.  After the initial TKL configuration screens, I tried to access ProjectPier via a browser.  The browser displayed the following error message:

Exception in AutoLoader: exception 'Exception' with message 'Could not find class file for "DB"' in /var/www/projectpier/environment/classes/AutoLoader.class.php:105 Stack trace: #0 /var/www/projectpier/environment/classes/AutoLoader.class.php(111): AutoLoader->loadClass('DB') #1 /var/www/projectpier/application/functions.php(32): AutoLoader->loadClass('DB') #2 /var/www/projectpier/init.php(94): __autoload('DB') #3 /var/www/projectpier/index.php(11): require('/var/www/projec...') #4 /var/www/projectpier/public/index.php(9): require('/var/www/projec...') #5 {main}

I logged into :12321 and went to the MySQL Server section.  After doing that - and nothing else, simply viewing the page - ProjectPier was then able to display the configuration page in the browser.

I hope this helps someone else out.