Comment 19 for bug 688225

Kyle,

the fix has been committed in commit #375 in magentorpconnect. You should also update you base_external_referentials module to rev #5187 at least and also reload you instance mapping "reload mappings" button.
This force to lookup order line products by SKU rather than product_id as the SKU seems to have the priority over the product_id anyway. If no SKU is found and you order get linked to some product having the same product_id as the unfound sku, well you are very bad lucky, but in any case your Magento order would have a problem (as it would reference SKU that don't exist in Magento), I think its reasonable to assume it will be rare enough so we do nothing about it.