Add to cart error

[jaimwa]

Hey guys

Hoping someone can help.

I'm using VM 1.5 on Joomla 1.5.20 and when I click add to cart on this page http://www.dominickirwan.com/index.php?page=shop.product_details&flypage=flypage.tpl&product_id=1&category_id=2&option=com_virtuemart&Itemid=179

I get the following error in a popup box:

Fatal error: Call to undefined method JDocumentRAW::addCustomTag() in /home/dominick/public_html/libraries/joomla/application/application.php on line 960

Any ideas?

Many thanks