Why is my C# Script blowing up?

I have a pretty simple SSIS C# Script which attempts to unzip and store a .zip file.

#region Help:  Introduction to the script task
/* The Script Task allows you to perform virtually any operation that can be accomplished in
 * a .Net application within the context of an Integration Services control flow.
 *
 * Expand the other regions which have "Help" prefixes for examples of specific ways to use
 * Integration Services features within this script task. */
#endregion


#region Namespaces
using System;
using System.Data;
using Microsoft.SqlServer.Dts.Runtime;
using System.Windows.Forms;
using System.IO.Compression;
using System.IO;
#endregion

namespace ST_1f613bef25864d8cb0aded9bf64e60dd
{
    /// <summary>
    /// ScriptMain is the entry point class of the script.  Do not change the name, attributes,
    /// or parent of this class.
    /// </summary>
	[Microsoft.SqlServer.Dts.Tasks.ScriptTask.SSISScriptTaskEntryPointAttribute]
	public partial class ScriptMain : Microsoft.SqlServer.Dts.Tasks.ScriptTask.VSTARTScriptObjectModelBase
	{
        #region Help:  Using Integration Services variables and parameters in a script
        /* To use a variable in this script, first ensure that the variable has been added to
         * either the list contained in the ReadOnlyVariables property or the list contained in
         * the ReadWriteVariables property of this script task, according to whether or not your
         * code needs to write to the variable.  To add the variable, save this script, close this instance of
         * Visual Studio, and update the ReadOnlyVariables and
         * ReadWriteVariables properties in the Script Transformation Editor window.
         * To use a parameter in this script, follow the same steps. Parameters are always read-only.
         *
         * Example of reading from a variable:
         *  DateTime startTime = (DateTime) Dts.Variables["System::StartTime"].Value;
         *
         * Example of writing to a variable:
         *  Dts.Variables["User::myStringVariable"].Value = "new value";
         *
         * Example of reading from a package parameter:
         *  int batchId = (int) Dts.Variables["$Package::batchId"].Value;
         *
         * Example of reading from a project parameter:
         *  int batchId = (int) Dts.Variables["$Project::batchId"].Value;
         *
         * Example of reading from a sensitive project parameter:
         *  int batchId = (int) Dts.Variables["$Project::batchId"].GetSensitiveValue();
         * */

        #endregion

        #region Help:  Firing Integration Services events from a script
        /* This script task can fire events for logging purposes.
         *
         * Example of firing an error event:
         *  Dts.Events.FireError(18, "Process Values", "Bad value", "", 0);
         *
         * Example of firing an information event:
         *  Dts.Events.FireInformation(3, "Process Values", "Processing has started", "", 0, ref fireAgain)
         *
         * Example of firing a warning event:
         *  Dts.Events.FireWarning(14, "Process Values", "No values received for input", "", 0);
         * */
        #endregion

        #region Help:  Using Integration Services connection managers in a script
        /* Some types of connection managers can be used in this script task.  See the topic
         * "Working with Connection Managers Programatically" for details.
         *
         * Example of using an ADO.Net connection manager:
         *  object rawConnection = Dts.Connections["Sales DB"].AcquireConnection(Dts.Transaction);
         *  SqlConnection myADONETConnection = (SqlConnection)rawConnection;
         *  //Use the connection in some code here, then release the connection
         *  Dts.Connections["Sales DB"].ReleaseConnection(rawConnection);
         *
         * Example of using a File connection manager
         *  object rawConnection = Dts.Connections["Prices.zip"].AcquireConnection(Dts.Transaction);
         *  string filePath = (string)rawConnection;
         *  //Use the connection in some code here, then release the connection
         *  Dts.Connections["Prices.zip"].ReleaseConnection(rawConnection);
         * */
        #endregion


		/// <summary>
        /// This method is called when this script task executes in the control flow.
        /// Before returning from this method, set the value of Dts.TaskResult to indicate success or failure.
        /// To open Help, press F1.
        /// </summary>
		public void Main()
		{
            String CMSNPIZipFileName = Dts.Variables["User::CMSNPIFileName"].Value.ToString();
            String CMSNPIFilePath = Dts.Variables["$Package::CMSNPIFileLocation"].Value.ToString();

            using (ZipArchive file=ZipFile.OpenRead(CMSNPIZipFileName))
            {
                foreach(ZipArchiveEntry entry in file.Entries)
                {
                    entry.ExtractToFile(Path.Combine(CMSNPIFilePath,entry.FullName));
                }
            }

            File.Delete(CMSNPIZipFileName);

			// TODO: Add your code here

			Dts.TaskResult = (int)ScriptResults.Success;
		}

        #region ScriptResults declaration
        /// <summary>
        /// This enum provides a convenient shorthand within the scope of this class for setting the
        /// result of the script.
        ///
        /// This code was generated automatically.
        /// </summary>
        enum ScriptResults
        {
            Success = Microsoft.SqlServer.Dts.Runtime.DTSExecResult.Success,
            Failure = Microsoft.SqlServer.Dts.Runtime.DTSExecResult.Failure
        };
        #endregion

	}
}

And this is the error I am getting when I attempt running my SSIS Package and seems really cryptique to me...

 at System.RuntimeMethodHandle.InvokeMethod(Object target, Object[] arguments, Signature sig, Boolean constructor)
   at System.Reflection.RuntimeMethodInfo.UnsafeInvokeInternal(Object obj, Object[] parameters, Object[] arguments)
   at System.Reflection.RuntimeMethodInfo.Invoke(Object obj, BindingFlags invokeAttr, Binder binder, Object[] parameters, CultureInfo culture)
   at System.RuntimeType.InvokeMember(String name, BindingFlags bindingFlags, Binder binder, Object target, Object[] providedArgs, ParameterModifier[] modifiers, CultureInfo culture, String[] namedParams)
   at Microsoft.SqlServer.Dts.Tasks.ScriptTask.VSTATaskScriptingEngine.ExecuteScript()

Can anyone help me out here???

Thanks for your review and am hopeful for a reply.