This issue is with BVCommerce 2004.5 or earlier. During the checkout process you may receive an error:
Message received is:
There was an error while attempting to save your order!
Access is denied. Click Here
<https://yourdomain.com/checkout_confirm.aspx> to check your
order and try again
This error is due to a flaw in this version of BVCommerce and in order to rectify this problem it's recommended you update to the latest build of BVCommerce (2004.7 or later). The problem is due to security permissions on a mutex being locked and unreadable when multiple BVCommerce stores exist on the same physical server and the application pool identities for each store differ.