SSIS Programming Model - Adding Custom Dll As An Executable To Package

I am trying to add a custom dll(IncrementTask avalilable in SQL Server DTS Samples)
as an executable(Task) to an SSIS package.


The following console application consumes the Custom dll:



using System;

using Microsoft.SqlServer.Dts.Runtime;

using Microsoft.SqlServer.Dts.Tasks.FileSystemTask;

using Microsoft.SqlServer.Dts.Samples;

using Microsoft.Samples.SqlServer.Dts;





namespace Microsoft.SqlServer.Dts.Samples



{

class Program

{

static void Main(string[] args)

{

Package p = new Package();

// Add a File System task to the package.

//This Line of code works fine.

//TaskHost execPkghost = (TaskHost)p.Executables.Add("STOCKQLTask");




//This line throws the following error: Object reference not set to an instance of an object.

TaskHost execPkghost = (TaskHost)p.Executables.Add("Microsoft.Samples.SqlServer.Dts.IncrementTaskUI,IncrementTaskCS,
Version=1.0.0.0,Culture=Neutral,PublicKeyToken=b23be0feabed1355");



TaskHost thFileSystemTask = execPkghost as TaskHost;



// Iterate through the package Executables collection.

Executables pExecs = p.Executables;

foreach (Executable pExec in pExecs)

{

TaskHost taskHost = (TaskHost)pExec;

Console.WriteLine("Type {0}", taskHost.InnerObject.ToString());

}

Console.Read();

}

}

}


I am getting a runtime error that "object reference has not been set to an instance of the object".
Any help on this is higly appreciated.