SOLVED:'TEMPLATE ERROR: Invalid data reference post.canonicalurl: No dictionary named: 'post' in: ['blog', 'skin', 'view'] '

This error appeared on every individual post after adding facebook comments.

What was causing this was the facebook comments appearing twice in my xml.

<fb:comments colorscheme='light' expr:href='data:post.canonicalUrl' expr:title='data:post.title' expr:xid='data:post.id' width='600'/>

As well as...

<div class='fb-comments' data-type='button' expr:href='data:post.canonicalUrl' expr:title='data:post.title' expr:xid='data:post.id' locale='el_GR' width='600'/>

And this was causing a conflict.

So I removed the fb:comments and -problem solved.