Flex 3 to Flex 4.5.1 Error (UIComponent)

Question

When I change flex 3 to flex 4.5. I keep the almost code and change the essitial code to pass the complie of flex 4.5
But when I did the debug, the system just the fault at the webservice module.
The server dispatch event to the webservice which connect to the C# then just out
private function callLaterDispatcher(event:Event):void
// trace(">>calllaterdispatcher " + this);
UIComponentGlobals.callLaterDispatcherCount++;
// At run-time, callLaterDispatcher2() is called
// without a surrounding try-catch.
if (!UIComponentGlobals.catchCallLaterExceptions)
callLaterDispatcher2(event);
// At design-time, callLaterDispatcher2() is called
// with a surrounding try-catch.
else
try
callLaterDispatcher2(event);
catch(e:Error)
// Dispatch a callLaterError dynamic event for Design View.
                var callLaterErrorEvent:DynamicEvent = new DynamicEvent("callLaterError");
callLaterErrorEvent.error = e;
callLaterErrorEvent.source = this;
                systemManager.dispatchEvent(callLaterErrorEvent);
// trace("<<calllaterdispatcher");
UIComponentGlobals.callLaterDispatcherCount--;
In the file of UIComponent.as the error happens in the red line when I did the debug 
It connect to the event and also related in the error log
TypeError: Error #1009: Cannot access a property or method of a null object reference.
  at com.iqity.fusion.iqzone.commands.charts.realTimeProcessMonitor::LoadRealTimeProcessMonito rChartDataCommand/responseCorrectHandler()[C:\Users\Devel\Adobe Flash Builder 4.5\IQFlex4.5\src\com\iqity\fusion\iqzone\commands\charts\realTimeProcessMonitor\LoadReal TimeProcessMonitorChartDataCommand.as:802]
  at com.iqity.fusion.iqzone.business::IQFusionResponder/result()[C:\Users\Devel\Adobe Flash Builder 4.5\IQFlex4.5\src\com\iqity\fusion\iqzone\business\IQFusionResponder.as:108]
  at mx.rpc::AsyncToken/http://www.adobe.com/2006/flex/mx/internal::applyResult()[E:\dev\4.5.1\frameworks\projects\rpc\src\mx\rpc\AsyncToken.as:239]
  at mx.rpc.events::ResultEvent/http://www.adobe.com/2006/flex/mx/internal::callTokenResponders()[E:\dev\4.5.1\frameworks\projects\rpc\src\mx\rpc\events\ResultEvent.as:207]
  at mx.rpc::AbstractOperation/http://www.adobe.com/2006/flex/mx/internal::dispatchRpcEvent()[E:\dev\4.5.1\frameworks\projects\rpc\src\mx\rpc\AbstractOperation.as:244]
  at mx.rpc::AbstractInvoker/http://www.adobe.com/2006/flex/mx/internal::resultHandler()[E:\dev\4.5.1\frameworks\projects\rpc\src\mx\rpc\AbstractInvoker.as:318]
  at mx.rpc::Responder/result()[E:\dev\4.5.1\frameworks\projects\rpc\src\mx\rpc\Responder.as:5 6]
  at mx.rpc::AsyncRequest/acknowledge()[E:\dev\4.5.1\frameworks\projects\rpc\src\mx\rpc\AsyncR equest.as:84]
  at DirectHTTPMessageResponder/completeHandler()[E:\dev\4.5.1\frameworks\projects\rpc\src\mx\ messaging\channels\DirectHTTPChannel.as:451]
  at flash.events::EventDispatcher/dispatchEventFunction()
  at flash.events::EventDispatcher/dispatchEvent()
  at flash.net::URLLoader/onComplete()

Answer 1

You may want to check out what is going on in your library.  I would start where the error message gives us a hint, LoadRealTimeProcessMonitorChartDataCommand.as:802