Unwanted source code appears in browser but not in Dreamweaver Code Window

Question

I am using templates and css, and Dreamweaver to build a new website of about 20 pages. With the first several pages, everything was working well. Then as I continued to add pages, I started to notice some code appearing at the bottom of web pages (under the footer), and then, a page duplicating the footer, and then, the drop-down function on the index page not working (pulls down and pops right back up) while headers on other pages work fine. I viewed the source code in the browsers (IE and Firefox) and I see the extra code at the bottom. However, this code doesn't show up in Dreamweaver, or, when I open the files in Notepad.
Following is an example of the different bottom-most lines of code in the Firefox browser compared to what I see in Dreamweaver or Notepad (note the highlighted line that is not showing up in Notepad or Dreamweaver).
Firefox Browser:
</div>
      </div>
      <div class="clear"></div>
    </div>
  </div>
</div>
<!-- InstanceEndEditable --><script src="http://brandbar.oit.duke.edu/footer/videos_podcasts_full.php" type="text/javascript"></script>
<script type="text/javascript"  src="http://brandbar.oit.duke.edu/header/js/jquery.min.js"></script>
<script type="text/javascript" src="http://brandbar.oit.duke.edu/header/js/globalHeader.js"></script> 
<script type="text/javascript"  src="http://brandbar.oit.duke.edu/footer/js/footer.js"></script>
</body>
<!-- InstanceEnd --></html>ript> 
<script type="text/javascript"  src="http://brandbar.oit.duke.edu/footer/js/footer.js"></script>
</body>
<!-- InstanceEnd --></html>
Notepad or Dreamweaver code screen:
</div>
      </div>
      <div class="clear"></div>
    </div>
  </div>
</div>
<!-- InstanceEndEditable --><script src="http://brandbar.oit.duke.edu/footer/videos_podcasts_full.php" type="text/javascript"></script>
<script type="text/javascript"  src="http://brandbar.oit.duke.edu/header/js/jquery.min.js"></script>
<script type="text/javascript" src="http://brandbar.oit.duke.edu/header/js/globalHeader.js"></script> 
<script type="text/javascript"  src="http://brandbar.oit.duke.edu/footer/js/footer.js"></script>
</body>
<!-- InstanceEnd --></html>

Answer 1

this answer is a bit late, but i think i have figured this problem out and it is probably still bugging someone out there.
i was having the same issues through many dreamweaver upgrades and kept running into the same problem (only on my Mac though - PC never gave me trouble). anyway, my hard drive recently died and i had a brand new one installed and then i installed a fresh version of CS5. started building a page and ran into the same problem. now that this is happening on a new drive with a fresh OS and reinstalled software, i needed to look elsewhere.
the problem is so simple you will more than likely cry at the amount of time you have wasted on it. more than likely if this is happening to you, you are working off of a network drive or a server. all my files are stored on a server locally, so when i make a change it is saving to the server. either a bad or slow connection to the server and/or a server going bad will cause this issue.
take the same file that you are having problems with and save down to your desktop - then preview in a browser. so the solution is to build the entire site on your local drive and then FTP up to the live site when complete.
hope this helps.