I checked with the guy who runs Edisoft's Merchant software to process our EDI orders. He showed me how he posts and order from Merchant to (ACCPAC) Order Entry. We don't use ACCPAC OE anymore, but Merchant still thinks it's talking to ACCPAC. He showed me that the first time he ships an order from Adagio OE (using the Ship All button), he gets an error for every line item in the order. I didn't write down the exact error description, but it's something along the lines of 'error deleting entry from Order Detail'. I assume it has to do with moving the item quantities from the 'ordered' colum to the 'shipped' colum.
He acknowledges the errors and gets to post the order at the end. The next order he ships won't have those errors anymore. It's only the first order he ships after importing it from Merchant.
Anyway, I know there's nothing you guys can do about it and I doubt Edisoft is going to fix this... I just want to describe what happens in case someone else encounters this issue. Supposedly, Edisoft is working on a Merchant for Adagio version of its software. In the meantime, this will work for us.
Cheers,
Andre