C# – Converting RTF file to PDF in c#

I need to provide a functionality to convert a RTF/WORD file to PDF and send it as attachment in an email, for this i tried the code as shown below:

    // Create a new Microsoft Word application object
    Microsoft.Office.Interop.Word.Application word = new Microsoft.Office.Interop.Word.Application();

    // C# doesn't have optional arguments so we'll need a dummy value
    object oMissing = System.Reflection.Missing.Value;

    Document doc;
    protected void Page_Load(object sender, EventArgs e)
    {
        ConvertToPDF("test.doc");
    }

    void ConvertToPDF(string sFileName)
    {
        // Create a new Microsoft Word application object
        Microsoft.Office.Interop.Word.Application word = new Microsoft.Office.Interop.Word.Application();

        // C# doesn't have optional arguments so we'll need a dummy value
        object oMissing = System.Reflection.Missing.Value;

        Document doc;
        try
        {
            word.Visible = false;
            word.ScreenUpdating = false;

            DirectoryInfo dirInfo = new DirectoryInfo(Server.MapPath(".") + "\\TempDoc");
            FileInfo[] wordFile = dirInfo.GetFiles(sFileName);

            if (wordFile.Length > 0)
            {
                Object filename = (Object)wordFile[0].FullName;

                // Use the dummy value as a placeholder for optional arguments
                doc = word.Documents.Open2000(ref filename, ref oMissing,
                    ref oMissing, ref oMissing, ref oMissing, ref oMissing, ref oMissing,
                    ref oMissing, ref oMissing, ref oMissing, ref oMissing, ref oMissing);
                doc.Activate();

                object outputFileName = wordFile[0].FullName.Replace(".doc", "");
                object fileFormat = WdSaveFormat.wdFormatPDF;

                // Save document into PDF Formats
                doc.SaveAs2000(ref outputFileName, ref fileFormat, ref oMissing, ref oMissing, ref oMissing, ref oMissing, ref oMissing, ref oMissing, ref oMissing, ref oMissing, ref oMissing);
            }
        }
        catch (Exception ex)
        {
            Response.Write(ex);
        }
        finally
        {
            // Close the Word document, but leave the Word application open.
            // doc has to be cast to type _Document so that it will find the
            // correct Close method.
            doc = null;

            // word has to be cast to type _Application so that it will find
            // the correct Quit method.
            word = null;
        }

    }

But it gives error on
doc.SaveAs2000(ref outputFileName, ref fileFormat, ref oMissing, ref oMissing, ref oMissing, ref oMissing, ref oMissing, ref oMissing, ref oMissing, ref oMissing, ref oMissing);
statement.

This may have reason that we have Microsoft Office 2007 and in this, there is not any option to save as PDF file. While in Microsoft Office 2010 it has that option so this code may work when Microsoft Office 2010 is installed on server.