Good News! I finally made it to the ‘Your order has been submitted…’ message! Thanks a lot Hal for your help!

Here is how I did it!

The message ‘Queue is not registered in the DS’ can be ignored. There is no need to install Active Directory or any other LDAP server. Just install Message Queuing (only subcomponent ‘Common’ is needed). Create a new private queue called ‘orders’!
Clean up (delete all records) in the table ‘ShoppingCarts’ ! Log in, buy gadgets and it just works!