Hello, last friday I upgraded out shop from verison 5.0.8 to 6.2.0-b1 and now if a customer places an order he can put in the address data and at after address verification he gets error 404 at the page he should see his ordered goods. if I look at the error log I can see the data of the order and at the end of the message there is  the message - Duplicate entry '' for key 'custom_oid' how can I repair this? many thanks in advance.