Libertarianism is Anti-Capitalist?

Posted by Brad Warbiany, whose blog is here
in response to a post on David Friedman's blog

"Ahh, The Dispossessed. That brings up an interesting point. One interesting think about that book, as well as much of Heinlein's work (such as The Moon Is A Harsh Mistress), seems to be very negative towards the idea of a libertarian (or anti-capitalist) society ever actually existing."

My question: I thought Capitalism was the foundation and engine of Libertarianism? What would Libertarianism look like without Capitalism?

Yes, I know I could ask my question on one of their blogs, but my question isn't related to the post (it was about the Narnia movie, of all things!), and I'd need the answer in small words and short sentences because, to be honest, I know little about politics and next to nothing about economic theory. The answer is probably so obvious as to insult their intelligence by asking, and I may never read either The Dispossessed or anything else by Heinlein. What to do? So I'm throwing the question out into the dark hole of cyberspace.