SAP Message WRF_AT124 - System error while accessing already read allocation table data

Diagnosis The system cannot find the data record in table GT_AUPO_DB, although itwas already copied from table GT_AUPO_DB_ALL. The problem involves allocation table &V1&, item &V2&, which isreferenced by purchase order &V3&, item &V4&. Procedure Check the relationship between the named allocation table item and thepurchase order item.