I encountered the same problem a while back when i was trying to join a Google Plus Hangout and what's ironic is that it was hosted by Google itself, the AdSense team. I got the invitation, had the cheery "Join this hangout" button for the "Limited" hangout, but every time I clicked it, I'd get an error.

"Something's wrong with the network!" I thought. Those kind of errors are transient, though, and I could pop onto other sites while the Hangout was continually failing. That's not right! A little more paranoia and I figured something was broken in my computer. Fortunately, before I restarted the entire machine -- which, in fact, wouldn't have fixed the problem -- I did a Google search to see what was going on and if there was a known problem. I mean, I was using Google's own Web browser, Chrome, at the time, so it should be maximally compatible, right?

Turns out there's a known problem with how Chrome tries to speed up your Web browsing experience and once you fix it, you're good to go.

Let me show you, step by step.

First off, here's the Google Hangout invitation from Adam:

Try as I might, though, when I click on "Join this hangout", I got an error message:

Certainly looks ominous enough, doesn't it? How can the browser settings affect a DNS lookup? Turns out that Chrome uses what's called predictive network actions to maximize performance and, well, it doesn't always go well...

To disable this feature, simply go to the Preferences... option off the Chrome menu:

On Preferences select "Under the Hood" on the left, then you'll see the Privacy settings:

You want to disable "Predict network actions to improve page load performance", as I've highlighted above. Make that change, close the preferences window and go back to G+. Now click on the "Join this hangout" button and...

I'm IN! Now if only people were looking at the camera. :-)