Solution : https://service.sap.com/sap/support/notes/893885 (SAP Service marketplace login required)
Key words : 
system issues message dh 802, 'document number' input field, transfer price allocation reason, transfer price agreement, document numbers, project definition, documents exist, terms cjf2, program error, solution implement
Related Notes : 
       
| 1140770 | FAQ: F4-Help Cost Assignment |