I received something similar on a 4.3 to 4.5 with JobOps - mine referenced the SO Header. I rebuilt the SO_SalesOrderHistoryHeader and SO_SalesOrderHeader files in 4.3. Then deleted the MAS_XXX in the 4.5 install and copied the 4.3 MAS_XXX to the 4.5 location, started conversion again and all converted properly. Hope this helps