I tried this myself, and I have to say that in the tutorial it is not very clear where to insert the div block.
Here is what I did in addition to the instructions on the tutorial page:
I pasted this div fragment into the existing main div block index.html.
<div id="main" class="lift:surround?with=default;at=content"> <div class="lift:comet?type=Chat"> <ul> <li>line</li> </ul> </div> </div>
That should do it.
After launching the pier, I could use a simple chat application.
Here is a screenshot of what I see after running sbt ~jetty-run 
Hope Thomas helps
Btw, it even works with lift_blank:

Thomas Rawyler
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