Creating Word Document using OpenXml

I am creating a sample document using the code below.

public static void CreateDocumentFile(string file)
       {
           // Create a Wordprocessing document.
           using (WordprocessingDocument package = WordprocessingDocument.Create(file, WordprocessingDocumentType.Document))
           {
               // Add a new main document part.
               package.AddMainDocumentPart();

               // Create the Document DOM.
               package.MainDocumentPart.Document =
                 new Document(
                   new Body(
                     new Paragraph(
                       new Run(
                         new Text("Hello World!")))));

               // Save changes to the main document part.
               package.MainDocumentPart.Document.Save();
           }

Document is created at the desired location but when i open it, gives me an error ,

The file cannot be opened because there are some problem in the content and it is pointing that my document.xml file contains error on line:1 col:198

my document.xml contains

<pre lang="xml"><?xml version="1.0" encoding="utf-8"?><w:document xmlns:w="http://schemas.openxmlformats.org/wordprocessingml/2006/main"><w:body><a:p xmlns:a="http://schemas.openxmlformats.org/drawingml/2006/main"><a:r><a:t>Hello World!</a:t></a:r></a:p></w:body></w:document>

Tags: C# (C# 4.0)