Error posting sales shipment- "order must be completely pre-invoiced"

Using NAV 5.0, without MRP or the warehousing granule.

One of my employees is not able to post Sales Shipments after selecting the Item Tracking Lines in the Sales Order Shipping form. The error message is “The order must be completely pre-invoiced…” I don’t understand the reason for the error message since the customer is not on prepayment. Also, it only happens with this one login (though the premissions for this person are the same as everyone elses.)

Other users are able to successfully post the Sales Shipments so we are not “down” but I need to figure this out soon. Thanks for your thoughts.

Is this the same user you speak about in your other post Posting date not in your allowed posting range?

No, they are 2 different users. I have a world of problems this week.