This is what you need to do to make it work with VM 1.1:
In modules/mod_virtuemart_s5_column_cart.php change line 135 from:
$tax_total = $CURRENCY_DISPLAY->getRounded( $order_taxable );
to
$tax_total = round( $order_taxable );
It worked for me and hopefully anyone else that needs this fix will see this post.