It apears that it was NOT a minor writing error which resulted in Halbig

Though he denies that Obamacare was written in a way to deny subsidies to states that opted not to participate in the system, calling his January 2012 comments a “speak-o,” a second instance of Gruber making the same argument has been uncovered by Reason’s Peter Suderman.
Here are the two comments, both of which were made in January 2012. First, here’s Gruber at an event hosted by Noblis, a Virginia-based research nonprofit, on January 18, 2012 via Suderman. You can listen for yourself here:

What’s important to remember politically about this is if you’re a state and you don’t set up an exchange, that means your citizens don’t get their tax credits — but your citizens still pay the taxes that support this bill. So you’re essentially saying [to] your citizens you’re going to pay all the taxes to help all the other states in the country. I hope that that’s a blatant enough political reality that states will get their act together and realize there are billions of dollars at stake here in setting up these exchanges. But, you know, once again the politics can get ugly around this.

The second instance came on January 10, 2012 in a speech at the Jewish Community Center of San Francisco, again via Suderman. You can listen to the audio here:

Now a number of states have expressed no interest in doing so. A number of states—like California, has been a real leader—one of, I think it was the first state to pass an exchange bill. It’s been a leader in setting up its exchange. It’s a great example. But California is rare. Only about 10 states have really moved forward aggressively on setting up their exchanges. A number of states have even turned down millions of dollars in federal government grants as a statement of some sort—they don’t support health care reform.
Now, I guess I’m enough of a believer in democracy to think that when the voters in states see that by not setting up an exchange the politicians of a state are costing state residents hundreds and millions and billions of dollars, that they’ll eventually throw the guys out. But I don’t know that for sure. And that is really the ultimate threat, is, will people understand that, gee, if your governor doesn’t set up an exchange, you’re losing hundreds of millions of dollars of tax credits to be delivered to your citizens.

But Gruber wasn’t the only prominent Obamacare to make this argument. Then-Senate Finance Committee Chairman Max Baucus (D-MT), who ushered the law through the upper chamber in 2010, basically made the same point in a discussion with then-Sen. Jon Ensign (R-NV) over committee jurisdiction when the law was working its way through Congress.
The Obama admin meant to coerce states into creating exchanges, and punish them if they did not. This is no typo, and the courts have this RIGHT.