Here are the following steps on how to reproduce this bug report:
Confluence 4.1.x:

1. Go to any space and create a page
2. Click on 'Tools -> Export to Word'
3. Save the Word doc file
4. Open it with a text editor
5. This is the result:
   

Confluence 4.2.x:

1. Go to any space and create a page
2. Click on 'Tools -> Export to Word'
3. Save the Word doc file
4. Open it with a text editor or with a web browser as a HTML file
5. This is how it will look like (notice the additional email header lookalike, it's also there at the bottom but not in this screen shot):