Error Message "Unable to add control" opening FF reports panel

Products

• CA Network Flow Analysis (NetQos / NFA)

Issue/Introduction

From time to time the following error message in the NFA GUI for FF reports :
Unable to add control: Object reference not set to an instance of an object.
Control: /RA/Ctrls/ReportBrowser.ascx at NQ.RA.Business.AgentPhysical.GetByRouterAddressInterfaceIndex(IPAddress routerAddress, UInt32 ifIndex, IFileLog iFileLog) [...]

Environment

win2012
NFA 9.3.x

Cause

some Forensic Report have failed during last run and put a long error msg in the
reporter.flowforensicsreport_definitions table  .

this msg cannot be displayed as exceding the javascript variable size .

Resolution

clear  the error status for the FF reports in error from the mysql reporter.flowforensicsreport_definitions table :
mysql reporter
update flowforensicsreport_definitions set LastExecutionError=NULL ;
quit;