Event log Return OverTime

Hi Guys:

Recently ,I met a problem as follow:
When I try to read the system message use C# by PCSDK, it return the error like this
"function calculate overtime " "Because of function calculating overtime ,function calculate was forbidden ",Then I try to read the others message ,but return the same
my code like this :
private EventLog mCurrentEvent = GudData.mController.EventLog;
private void CmdUpdataMessage_Click(object sender, EventArgs e)
{
EventLogCategory wMessage= mCurrentEvent.GetCategory(CategoryType.System);
EventLogMessage msg = wMessage.Messages[1];
}
I’m sure there are two message in wMessage,
does someone can help me ?
Thanks