C# Powershell snapin not registering using installutil

Question

I've got a really simple powershell script (see below). I've got installutil aliased using the following in my profile:

set-alias installutil $env:windir\Microsoft.NET\Framework\v2.0.50727\installutil

In powershell I simply:

installutil assemplylocation.dll

This returns successfully. (Install/Commit both complete successfully). Yet when I check the registry, or in powershell using get-pssnapin -registered it doesn't show my assembly. I did this the other day and it worked fine, but I don't seem to be able to duplicate it ... please advise.

using System;
using System.Management.Automation;
using System.ComponentModel;

namespace PSBook_2_1
{
    [RunInstaller(true)]
    public class PSBookChapter2MySnapIn : PSSnapIn
    {
        public PSBookChapter2MySnapIn()
            : base()
        { }

    // Name for the PowerShell snap-in.
    public override string Name
    {
        get
        {
            return "Wiley.PSProfessional.Chapter2";
        }
    }

    // Vendor information for the PowerShell snap-in.
    public override string Vendor
    {
        get
        {
            return "Wiley";
        }
    }

    // Description of the PowerShell snap-in
    public override string Description
    {
        get
        {
            return "This is a sample PowerShell snap-in";
        }
    }
}

// Code to implement cmdlet Write-Hi
[Cmdlet(VerbsCommunications.Write, "Hi")]
public class SayHi : Cmdlet
{
    protected override void ProcessRecord()
    {
        WriteObject("Hi, World!");
    }
}

// Code to implement cmdlet Write-Hello
[Cmdlet(VerbsCommunications.Write, "Hello")]
public class SayHello : Cmdlet
{
    protected override void ProcessRecord()
    {
        WriteObject("Hello, World!");
    }
}

}

Answer 1

downatone's answer put me on the right track but my problem was the opposite way round. My project is set to any CPU and I am on Win7 x64 so the powershell being launched from my code and then installing the dll with the snapin was 64 bit. However the install command I used was pointing to the 32 bit .net runtime i.e.

C:\Windows\Microsoft.net\Framework\V4.0.30319\installutil myDLL.dll

when it should have been

C:\Windows\Microsoft.net\Framework64\V4.0.30319\installutil myDLL.dll

Note the 64 in the Framework path.