Error on calling 'OnBarUpdate' method on bar -1

[fingers]

can someone advise ...

private Series<double mySeries;
protected override void OnStateChange()
{
if (State == State.Configure)
{
AddDataSeries(BarsPeriodType.Tick, 1);
}
else if (State == State.DataLoaded)
{
mySeries = new Series<double>(this);
}
}
protected override void OnBarUpdate()
{
if (CurrentBars[BarsInProgress] <= 1)
return;
if (BarsInProgress == 1)
mySeries[0] = 1;
}

but get this error "Error on calling 'OnBarUpdate' method on bar -1 ... "

[NinjaTrader_ChelseaB]

Hello fingers,

if (BarsInProgress == 1 && CurrentBars[0] > 0)
mySeries[0] = 1;