duplicate meta description

Hello, I am trying to fix my duplicate meta descrioption problem… Here is the source code..

<!-- This site is optimized with the Yoast WordPress SEO plugin v1.3.4.1 - http://yoast.com/wordpress/seo/ -->
<meta name="description" content="10 Simple WordPress Themes for download that can be easily customized to fit your web design needs. These simple but elegant themes are available for free."/>
<link rel="canonical" href="http://develop-a-website.com/10-simple-wordpress-themes" />
<meta property='og:locale' content='en_US'/>
<meta property='og:title' content='10 Simple WordPress Themes for free'/>
<meta property='og:description' content='10 Simple WordPress Themes for download that can be easily customized to fit your web design needs. These simple but elegant themes are available for free.'/>
<meta property='og:url' content='http://develop-a-website.com/10-simple-wordpress-themes'/>
<meta property='og:site_name' content='develop-a-website.com'/>
<meta property='og:type' content='article'/>
<meta property='og:image' content='http://develop-a-website.com/wp-content/uploads/2013/01/10-simplethemes.jpg'/>
<meta property='og:image' content='http://www.develop-a-website.com/wp-content/themes/nest/images/nest.jpg'/>
<meta property='og:image' content='http://www.develop-a-website.com/wp-content/themes/nest/images/responsive.jpg'/>
<meta property='og:image' content='http://www.develop-a-website.com/wp-content/themes/nest/images/brightpage.jpg'/>
<meta property='og:image' content='http://www.develop-a-website.com/wp-content/themes/nest/images/platform.jpg'/>
<meta property='og:image' content='http://www.develop-a-website.com/wp-content/themes/nest/images/whiteboard.jpg'/>
<meta property='og:image' content='http://www.develop-a-website.com/wp-content/themes/nest/images/deux.jpg'/>
<meta property='og:image' content='http://www.develop-a-website.com/wp-content/themes/nest/images/convention.jpg'/>
<meta property='og:image' content='http://www.develop-a-website.com/wp-content/themes/nest/images/clean-retina.jpg'/>
<meta property='og:image' content='http://www.develop-a-website.com/wp-content/themes/nest/images/elegantWhite.jpg'/>
<meta property='og:image' content='http://www.develop-a-website.com/wp-content/themes/nest/images/spun.jpg'/>
<!-- / Yoast WordPress SEO plugin. -->

to me it looks like it is coming from your plugin. I don’t know what to change to fix this problem. Please advise as I believe I am being penalized by google for duplicate meta desc. Thanks.

http://ww.wp.xz.cn/extend/plugins/wordpress-seo/