A receipt in another receipt register currently being processed is referencing the same purchase order as a receipt in this register. Run this register again when the other process is complete.
I see the Sage KB suggestion [here](https://goo.gl/R62aqc). Seems pretty good. If you only have one PO in the batch. What happens when you have multiple POs? Just start reinitializing the PO_ReceiptVarianceCalculation.M4T and hope for the best?
If Sage can kick this error out shouldn't they know the offending PO # and be able to print it on the error report?
Maybe I'm missing something really obvious?