Hi Same problem,
Installed for the first time today, version 1.8.4.4
Deactivated, cleared cache then activated and proplem came back.
Warning: Invalid argument supplied for foreach() in /home/bar49842/public_html/wp-content/plugins/participants-database/classes/PDb_Settings.class.php on line 141
Click on “Settings” displays “Sorry, you are not allowed to access this page”
