NAsm error with c# and Cosmos

Question

I am trying to build a small operating system using c# and Cosmos
At fisrt this went pretty good only from one moment to the other it stoped working and gave me the following error:

Error occurred while invoking NAsm.
OSBoot.asm Line: 241424 Code: push dword System_Void__System_IO_Stream_Dispose__
OSBoot.asm Line: 242633 Code: push dword System_Void__System_IO_Stream_Dispose__ t OSBoot.asm Line: 247640 Code: push dword System_Void__System_IO_Stream_Dispose__
OSBoot.asm Line: 248618 Code: push dword System_Void__System_Collections_Generic_List_1_Enumerator__Commands_ICommand_ICommandBase_Dispose_

I even installed a new installation of Microsoft Visual studio with cosmos on a new system and started over from scratch, at first it worked but asgain withoud any chage it stopped working

using System;
using Commands;
using Sys = Cosmos.System;

namespace OS
{
public class Kernel : Sys.Kernel
{
    private Env SysEnv { get; set; }
    private InputHandeler InputHandler { get; set; }


    protected override void BeforeRun()
    {
        Console.WriteLine("Creating Enviriment...");
        SysEnv = new Env();
        InputHandler = new InputHandeler(new CommandLister());
        Console.WriteLine("Enviriment build");
        Console.Clear();
        Console.WriteLine("Os booted successfully.");
    }

    protected override void Run()
    {
        Console.Write(SysEnv.ConsolCommandPrefix);
        var input = Console.ReadLine();
        try
        {
            InputHandler.ExecuteInput(input);
        } catch(Exception)
        {
            //TODO good exeption and the use of it
        }
    }
}
}

Env class

namespace OS
{
public class Env
{
    public string CurrentUser { get; set; }
    public string CurrnetDir { get; set; }
    private string prefix;
    public string ConsolCommandPrefix
    {
        get { return CurrentUser + "@" + CurrnetDir + prefix; }
        set { prefix = value; }
    }

    public Env()
    {
        ConsolCommandPrefix = "> ";
        CurrentUser = "Admin";
        CurrnetDir = "/";
    }
}
}

CommandLister class

using System;
using System.Collections.Generic;
using Commands.Command;
using Commands.Command.SystemCommands;
using Commands.ICommand;

namespace Commands
{
public class CommandLister
{
    private List<ICommandBase> KnownCommands { get; set; }
    private Unkown UnkownCommand { get; set; }

    public CommandLister()
    {
        KnownCommands = new List<ICommandBase>();
        addCommand(new Help());
        UnkownCommand = new Unkown();
    }

    public void addCommand(ICommandBase command)
    {
        KnownCommands.Add(command);
    }

    public ICommandBase getCommand(String input)
    {
        foreach (var command in KnownCommands)
        {
            if(true)
            {
                return command;
            }
        }
        return UnkownCommand;
    }

}
}

The other classes only contain some text and only print something to the Console

I have two questions: - What is causing this - How can i solve this problem

Edit: i tried it again ron an other OS (i used vista the first time), this time i used Windows 7. The same thing happend at first it worked (i started from scratch again..) but after a few builds and runs it somehow broke again. even when undoing the changes i made. it wont build anymore.

Kind regards,

Edo Post