The problem I believe is that that script is for use with jQuery, and you don’t have jQuery attached to your site. Put this line of code in your head, it links to the jquery code so it will be usable on your site.
After you put that line of code in. Try adding the scrollTo code again. Make sure to add the scrollTo script AFTER the the above jquery one. Also, make sure your id’s and classes match properly with what scrollTo says they need to be.