Using RSystemAgent with TSysAgentEvent and RSAVarChangeNotify

I m trying to monitor some system varibles like battery strength and network strength etc using the classes RSystemAgent, TSysAgentEvent and RSAVarChangeNotify.

This is the code i m writing ....

#include "CBatteryReader.h"
CBatteryReader::CBatteryReader(MBatteryObserver* aOb):CActive(0),iBatteryObserver(aOb)
{
}
CBatteryReader::~CBatteryReader()
{
//delete iBatteryObserver;
iSystemAgent.Close();
Cancel();
}
CBatteryReader* CBatteryReader::NewL(MBatteryObserver* aOb)
{
	CBatteryReader* self = new(ELeave) CBatteryReader(aOb);
	CleanupStack::PushL( self );
	self->ConstructL();
	CleanupStack::Pop();		
	return self;
}
void CBatteryReader::ConstructL()
{
	User::LeaveIfError(iSystemAgent.Connect());
	iSysAgentEvent.SetRequestStatus(iStatus);
	iSysAgentEvent.SetUid(KUidBatteryStrength);
	CActiveScheduler::Add( this );
}
TInt CBatteryReader::GetBatteryState()
{
	//iSysAgentEvent.SetRequestStatus(iStatus);
   	//iSysAgentEvent.SetUid(KUidBatteryStrength);
   	iSystemAgent.NotifyOnEvent(iSysAgentEvent);
    SetActive();
//return 0;//(iSystemAgent.GetState(KUidBatteryStrength));
}
void CBatteryReader::RunL()
{
TInt state = iSystemAgent.GetState(iSysAgentEvent.Uid());
// do what you want with state here
iBatteryObserver->OnBatteryChange(iSysAgentEvent.State());
//Reenable
//GetBatteryState();
}
void CBatteryReader:😃oCancel()
{ 
}
TInt CBatteryReader::RunError( TInt aError )
{
}

but i receive a Panic Code 36 CONE
which says

Open handles were found during application shutdown

ANy clues ????