FYI - I saw you posted the same question to NextGEN Facebook OG's support section. Here's another copy of my answer:
For the Facebook issue, you have some duplicate author meta tags on your page at http://yeow.com.ar/2012/11/arrestado-hombre-por-pensar-en-sexo.html :
<meta name="author" content="Nahuel Sanchez"/>
<meta property="article:author" content="http://yeow.com.ar/author/Yeow/" />
The second meta tag is from NextGEN Facebook OG and is in the correct OG format for Facebook. The first is from something else (an SEO plugin perhaps?), and this is the one Facebook is complaining about.
You can leave them both there - Facebook is only warning you about it. You could also remove the first tag, or disable the second tag from the NextGEN Facebook OG's settings page.
I'd leave the NextGEN Facebook OG meta tag, since it is in the correct format for Facebook. ;-)
The warnings you are getting from Google are not for the Facebook OG tags, but other tags in your content which may -- according to Google -- be incomplete. Support for other microformats, like the hCard http://microformats.org/wiki/hcard mentioned, is outside the scope of NextGEN Facebook OG's target functionality.