Thank you for the helpful reply. For the interests of anyone else having this problem in future I am posting the solution: When I enabled the error log the following error: Fatal error: Call to undefined method Example_Customer_Backend::hasPerIncidentContract() in /var/www/eventum/include/class.customer.php on line 379 This lead me to find that while the example customer integration does not use "per incident" (as is mentioned in the code and on the eventum site), the value of hasPerIncidentContract() is not set. Therefore add the following method into class.example.php

/** * Returns true if the customer backend uses incident contracts, false otherwise * * @return boolean True if the project uses incident contracts. */ function hasPerIncidentContract() { return false; }