Office Merge Fields from Sharepoint list

Hi guys,

i am writing a SharePoint event recivers that fill a word template Mergefield from a SharePoint list filed. When i debug the code i recive this COM exception

"Word was unable to read this document.  It may be corrupt.

This is my code:

using System;
using System.Security.Permissions;
using Microsoft.SharePoint;
using Microsoft.SharePoint.Utilities;
using Microsoft.SharePoint.Workflow;
using Microsoft.Office.Interop.Word;

namespace MeetingReportTemplate.ToWordTemplate
{
    /// <summary>
    /// List Item Events
    /// </summary>
    public class ToWordTemplate : SPItemEventReceiver
    {
        /// <summary>
        /// An item was updated.
        /// </summary>
        public override void ItemUpdated(SPItemEventProperties properties)
        {
            base.ItemUpdated(properties);

            SPListItem currentItem = properties.ListItem;

            if (currentItem["Stampa"].ToString() == "Yes")
            {

                string ProtocolText = currentItem["Protocol Text"].ToString();


                Object oMissing = System.Reflection.Missing.Value;

                Object oTemplatePath = "C:\\Users\\Administrator\\Desktop\\Protocol2014.dotx";


                Application wordApp = new Application();
                Document wordDoc = new Document();

                wordDoc = wordApp.Documents.Add(ref oTemplatePath, ref oMissing, ref oMissing, ref oMissing);

                foreach (Field myMergeField in wordDoc.Fields)
                {


                    Range rngFieldCode = myMergeField.Code;

                    String fieldText = rngFieldCode.Text;



                    // ONLY GETTING THE MAILMERGE FIELDS

                    if (fieldText.StartsWith(" MERGEFIELD"))
                    {

                        // THE TEXT COMES IN THE FORMAT OF

                        // MERGEFIELD  MyFieldName  \\* MERGEFORMAT

                        // THIS HAS TO BE EDITED TO GET ONLY THE FIELDNAME "MyFieldName"

                        Int32 endMerge = fieldText.IndexOf("\\");

                        Int32 fieldNameLength = fieldText.Length - endMerge;

                        String fieldName = fieldText.Substring(11, endMerge - 11);

                        // GIVES THE FIELDNAMES AS THE USER HAD ENTERED IN .dot FILE

                        fieldName = fieldName.Trim();

                        // **** FIELD REPLACEMENT IMPLEMENTATION GOES HERE ****//

                        // THE PROGRAMMER CAN HAVE HIS OWN IMPLEMENTATIONS HERE

                        if (fieldName == "Text")
                        {

                            myMergeField.Select();

                            wordApp.Selection.TypeText(ProtocolText);

                        }

                    }

                }
                wordDoc.SaveAs("myfile.doc");
                wordApp.Documents.Open("myFile.doc");
                wordApp.Application.Quit();


            }



        }


    }
}