Activity log not generated

Hi, i am having problems generating activity log report. After hitting the activity log button, it just continues rolling and no report is generated.
We are running OJS 3.2.1.4.

Here is the error log:

PHP Fatal error: Uncaught Error: Call to a member function getStageId() on null in /www/var/data/ojs/htdocs/lib/pkp/classes/submission/SubmissionFileDAO.inc.php:768\nStack trace:
\n#0 /www/var/data/ojs/htdocs/lib/pkp/controllers/grid/eventLog/EventLogGridRow.inc.php(74): SubmissionFileDAO->getWorkflowStageId(Object(SupplementaryFile))
\n#1 /www/var/data/ojs/htdocs/lib/pkp/classes/controllers/grid/GridHandler.inc.php(1068): EventLogGridRow->initialize(Object(Request))
\n#2 /www/var/data/ojs/htdocs/lib/pkp/classes/controllers/grid/GridHandler.inc.php(985): GridHandler->_getInitializedRowInstance(Object(Request), 18, Object(SubmissionEventLogEntry))
\n#3 /www/var/data/ojs/htdocs/lib/pkp/classes/controllers/grid/GridHandler.inc.php(1033): GridHandler->renderRowsInternally(Object(Request), Array)
\n#4 /www/var/data/ojs/htdocs/lib/pkp/classes/controllers/grid/GridHandler.inc.php(923): GridHandler->renderGridBodyPartsInternally(Object(Request))
\n#5 /www/var/data/ojs/htdocs/lib/pkp/classes/controllers/grid/GridHandler.inc.php(645): GridHandler-> in /www/var/data/ojs/htdocs/lib/pkp/classes/submission/SubmissionFileDAO.inc.php on line 768

Thanks
Ahmed