Find the index.php file in your Joomla (Not virtuemart) template, should be in templates/you_template_name relative to your web root.
Find the bit that says
<jdoc:include type="component" />
and immediately before it, put the following:
<jdoc:include type="message" />
E.g.
<jdoc:include type="message" /><jdoc:include type="component" />