Not so fast.  Wold Blitzer was introducing the topic of Television Ads.  This was a Spanish radio ad.  No wonder Romney didn't recognize it.  He doesn't have any ads in Spanish on TV.

  I did some homework about the ad. Factcheck.org backs up Romney.  Factcheck.org points out that Newt Gingrich was talking about Spanish. Newt had had to back peddle on the words he used and offer an explanation directly to the Spanish community. So this was not a lie by Mitt. Newt was wrong.

So here is Newt making those comments and, as reported by factcheck.org, backing off of them when he took fire.
I don't agree with the maker of this video that it was racist.  It was just foolish Bomb throwing-again.