Problem is I get this in all browsers I've tried - see attached
it's just a bog standard model link to trigger facebox...
<a rel="{handler: 'iframe', size: {x: 700, y: 550}}" id="terms-of-service" class="terms-of-service modal" href="/~wwwbetac/index.php/en/component/virtuemart/vendor/betacraft-clothing/tos?tmpl=component&Itemid=0">
the only reason it wouldn't work (i.e. what you are seeing is the correct page but not in the model) is if a javascript error prevented the facebox code from running
but you don't have any errors and all the other JS on that page works fine..
If you can get the error then you will need to research what the error is - see :
www.flexiblewebdesign.com/forum-virtuemart-2-template-puremart-support/523-the-easiest-way-to-solve-jquery-conflict-issues
the part about firebug as the console to see JS errors
Cheers