Ian is correct, you will struggle to validate your page when using social media like buttons. the code provided by the social media sites like google + and face book are not standards compliant scripts
you can show the counter for stumble uppon by changing the s attribute in the stumble upon script. change:
<script src="http://www.stumbleupon.com/hostedbadge.php?s=5&r=http%3A%2F%2Fwww.justvibe.co.uk"></script>
to:
<script src="http://www.stumbleupon.com/hostedbadge.php?s=2&r=http%3A%2F%2Fwww.justvibe.co.uk"></script>
in this code we changed s=5 to s=2
there are 6 possible badge designs for stumble upon, you select which to use through the s attribute.