Trying to Save a File in Excel with VB.NET

Ok my program is attached very simple, I get an error before I see the After Save text...

This exe works fine on my development machine but not on a different machine....

Unhandled Exception: System.Runtime.InteropServices.COMException (0x800A03EC): SaveAs method of Work
   at Microsoft.VisualBasic.CompilerServices.LateBinding.InternalLateCall(Object o, Type objType, St
ring[] paramnames, Boolean[] CopyBack, Boolean IgnoreReturn)
   at Microsoft.VisualBasic.CompilerServices.NewLateBinding.LateCall(Object Instance, Type Type, Str
uments, String[] ArgumentNames, Type[] TypeArguments, Boolean[] CopyBack, Boolean IgnoreReturn)
   at ConsoleApplication1.Module1.Main()
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Imports System.IO
Imports System.Console
 
Module Module1
 
    Sub Main()
 
        Dim excelApplication As Object = CreateObject("Excel.Application")
        Dim excelWorkbook As Object = excelApplication.Workbooks.Add()
 
        excelWorkbook = excelApplication.ActiveWorkbook
        WriteLine("Before Save")
        excelWorkbook.SaveAs(filename:="C:\Test", FileFormat:=56)
        WriteLine("After Save")
        Exit Sub
 
 
    End Sub
 
 
End Module