Validation Error - AddThis Social Buttons

I ran the validator on my <a 
href="http://www.adams-legal.com/Accidents/Morgantown-Car-Accident.html">Morgantown 
car accident law</a> website and discovered very few errors, but one of 
the ones that came up was related to social networking buttons that I 
added to my website. They are added through an external link and 
javascript from the addthis.com website. Is there a better way to add 
the social sharing buttons without using an external site?
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