Null object reference error when trying to access output of geoprocessing task

[DeepikaSingh]

I am coding in Flex and my geoprocessing task runs successfully, but when I try to use  the data of the resultant shapefiles I get a runtime error.
Error#1009:Cannot access property or reference of a null object reference.
This is a part of my code where I get runtime error
public function jobComplete(event:GeoprocessorEvent)
{
                var paramValue:ParameterValue=event.executeResult.ParameterValue[0];
}
All the output shapefiles have been stored in Inetpub->wwwroot, and proper permission have been set for them using IIS.