It looks like there are 2 different type of errors being reported by the validator.
1. Those that reference meta tags help display your blog in twitter when people tweet a link. Please read more about this feature: https://dev.twitter.com/docs/cards There’s not much that can be done about these unfortunately.
2. Paragraphs that set the “align” attribute to “justify” or “center”. This code exists in your post’s content area and you can easily remove this by editing your post from the HTML tab. The code will look similar to this:
Removing these will get rid of most of the errors.