run-time error '429' activex component can't create object

I've created a simple application .net Class that converts an excel spreadsheet into a pdf file. I then get an Excel 2007 application to call this dll which works fine on my development machine.

However, when I deploy it on to a Vista machine, that has both the .net framework and Excel 2007, I get this error:

run-time error '429' activex component can't create object

Even though I am an administrator on the machine, I cannot seem to put signed .net dlls into the GAC.

Can someone please help me resolve this?

This is how I'm calling .net tlb file from Excel 2007.

Sub TestSub()<br>
 &nbsp;Dim printLibraryTest As PrintLibrary.Print<br>
 &nbsp;Set printLibraryTest = New PrintLibrary.Print <br>
 &nbsp; printLibraryTest.ConvertExcelToPdf <br>
End Sub <br>

This is .net library below.

using System;<br>
using System.Collections.Generic;<br>
using System.Runtime.InteropServices;<br>
using System.Text;<br>
using Microsoft.Office.Interop.Excel;<br><br>

namespace PrintLibrary<br>
{<br>
    [ClassInterface(ClassInterfaceType.None)]<br>
    [Guid("3d0f04d2-9123-48e0-b12f-6c276ff2281b")]<br>
    [ProgId("PrintLibrary.Test")]<br>
    public class Print<br>
    {      <br>
        public void ConvertExcelToPdf(string inputFile,string outputFile)    <br>
        {    <br>
          &nbsp;&nbsp;  ApplicationClass excelApplication = new ApplicationClass();    <br>
          &nbsp;&nbsp;   Workbook excelWorkBook = null;    <br>
          &nbsp;&nbsp;  string paramSourceBookPath = inputFile;    <br>
          &nbsp;&nbsp;   object paramMissing = Type.Missing;    <br>

          string paramExportFilePath = outputFile;
          XlFixedFormatType paramExportFormat = XlFixedFormatType.xlTypePDF;
          XlFixedFormatQuality paramExportQuality =
          XlFixedFormatQuality.xlQualityStandard;
          bool paramOpenAfterPublish = false;
          bool paramIncludeDocProps = true;
          bool paramIgnorePrintAreas = true;
          object paramFromPage = Type.Missing;
          object paramToPage = Type.Missing;


            try
            {
                // Open the source workbook.
                excelWorkBook = excelApplication.Workbooks.Open(paramSourceBookPath,
                paramMissing, paramMissing, paramMissing, paramMissing,
                paramMissing, paramMissing, paramMissing, paramMissing,
                paramMissing, paramMissing, paramMissing, paramMissing,
                paramMissing, paramMissing);

                // Save it in the target format.
                if (excelWorkBook != null)
                    excelWorkBook.ExportAsFixedFormat(paramExportFormat,
                    paramExportFilePath, paramExportQuality,
                    paramIncludeDocProps, paramIgnorePrintAreas, paramFromPage,
                    paramToPage, paramOpenAfterPublish,
                    paramMissing);
            }
            catch (Exception ex)
            {
                // Respond to the error.
            }

Finally

            {
                // Close the workbook object.
                if (excelWorkBook != null)
                {
                    excelWorkBook.Close(false, paramMissing, paramMissing);
                    excelWorkBook = null;
                }

                // Quit Excel and release the ApplicationClass object.
                if (excelApplication != null)
                {
                    excelApplication.Quit();
                    excelApplication = null;
                }

                GC.Collect();
                GC.WaitForPendingFinalizers();
                GC.Collect();
                GC.WaitForPendingFinalizers();
            }  
        }
    }
}