I just tried a very basic Hello World type lib, and received an error -2146232576 (80131700) COM error when trying to CreateObject("MyClass") in a Excel macro, the assembly appeared in the reference list in th vba editor but on creation of object BOOM, that's why I asked the group, thanks anyway

This is the Excel macro

Sub Button1_Click()
Dim obj As CallingCSharpFromWord97.PJKWordClass

Set obj = CreateObject("CallingCSharpFromWord97.PJKWordClass")
obj.WriteLogFile "MS Word"

Set obj = Nothing

End Sub

And the C# class

using System;
using System.Collections.Generic;
using System.Text;
using System.IO;
using System.Runtime.InteropServices;

namespace CallingCSharpFromWord97
{
    
    public class PJKWordClass
    {
        public TextWriter tw = null;

        public PJKWordClass()
        {
        }

        public void WriteLogFile(string msg)
        {
            tw = new StreamWriter("c:\\PJKCalledFromWord97.log", true);
            tw.WriteLine(String.Format("This file was created by C# which was called from a COM client {0} at {1}",msg,DateTime.Now.ToLongDateString()));
            tw.Close();
        }

   }
}

The class is callable from VFP7 with no problem I think maybe it's a Office 97 issue.