Solution : https://service.sap.com/sap/support/notes/38252 (SAP Service marketplace login required)
Key words :
symptom transaction vf02/vf03 'billing -> document flow', additional key words document category, function 'environment -> document flow', 'document category' field, runtime error table_invalid_index, documents created prior, billing documents, error occurs, customer updates, solution p30k066133
Related Notes :
| 51504 | Cannot create cancellation billing doc. no log |
| 26124 | The field VBRP-VGTYP is not filled |