Hello!
The Add to cart-popup may not work in details and give the 406 error. Here is the fix:
open default.php in
\gk_bikestore_quickstart_J25\templates\gk_bikestore\html\com_virtuemart\productdetails
and delete line 251:
(<input type="hidden" name="virtuemart_manufacturer_id" value="<?php echo $this->product->virtuemart_manufacturer_id ?>" />)
Magnus