EDI Incoming Customer Order error

I disagree that it requires a code level investigation from IFS.  I also think the linked post is for a different sort of issue, though related to customers and EDI.

First, I would check the customer record itself.  The Customer Info missing type error can occur on the creation of the customer order if the customer record is not fully setup for the company in which the order is going to be created AND the addresses being used for the order.

For each address ID under the customer, check that Address Info is populated on the General Address Info tab and the Order Address Info tab (it is usually this one that is missing for one ID).  

After verifying the customer is setup correctly, another point of validation that would help is to create a customer order manually for that customer and verify that no errors are received using that customer with the current setup.

Finally if the customer is setup correctly, and the customer order creates correctly - manually - then confirm that the connection for the incoming EDI messages are connecting correctly.  Look at the Incoming Customer Order messages for this customer to see if there are further clues as to the cause of the error.

After verifying all of this is correct and assuming this customer has worked in the past and there have been no recent system changes that might have caused a change in behavior, only then would I go the route of entering a case with IFS.