Error when customer use discount code and 0 order value

[cassim]

TECHNICAL ERROR: unable to confirm the order Details: Error thrown: [object Object] Text status: error

So simpel can the code be when a customer is trying to checkout in our prestashop store.

 

The customer have a discountcode of the full value of 300 DKK 

The customer wants to buy a item for 299 DKK 

So the system will based on the settings need to create a new code for the customer with the value of 1 DKK

 

But the system don't even let him checkout with a order value on 0 DKK 

 

Anyone know how to fix this ?

 

I run 1.6.1.10 

[cassim]

any one ?