'ArgumentException Error on Compiling

[ak47ssss]

Hello,
I tried to compile my code and i got this error: The type or namespace name 'ArgumentException' could not be found (are you missing a using directive or an assembly reference?).
Here are my references:
using NinjaTrader.Cbi;
using NinjaTrader.Data;
using NinjaTrader.Gui.Chart;
using System;
using System.ComponentModel;
using System.Collections;
using System.Collections.Generic;
using System.ComponentModel;
using System.Drawing;
using System.Drawing.Drawing2D;
using System.Globalization;
using System.IO;
using System.Net;
using System.Text;
using System.Windows.Forms;
using System.Xml;
using System.Xml.Serialization;
Any help would be greatly appreciated.

[NinjaTrader_JC]

Hello ak47ssss,

Welcome to the NinjaTrader Support Forums!

What are you trying to call in the line that it has that error?