SERVER ERROR PROBLEM WITH RELATED PRODUCTS

[london]

Using Joomla 2.5.9 - VM 2.0.6 (issue still exists in  2.0.22a)

I am having a strange issue whereby whenever I have a product that has related products in it, a server error message appears as soon as someone tries to add the product to their shopping cart.  As soon as they hit add to cart they are presented with this message and are then completely unable to do anything else on the site (ie they can't add another product, view another product, go to home etc).  There is no message other than 'Server Error' that comes up.  It only happens on products that have related products associated with it. 

I have searched and searched to see if anyone else has reported or encountered this issue and have not found one topic on this.

This can be easily seen here:

http://www.duskmoth.com.au/index.php/component/virtuemart/women-s/skirts/peek-a-bow-knee-length-stretch-skirt-black-trim-detail?Itemid=0

Simply try adding this item to your cart

If anyone has any suggestions at all as to what I can do to fix this, I would be most appreciative.

Thank you.

[PRO]

the issue seems to be in the dropdown cart module

probably a php error