Solution : https://service.sap.com/sap/support/notes/335336 (SAP Service marketplace login required)
Key words : 
additional key words transaction mp38, start mass processing, period unit 't', error message 'factory_calendar_not_found', material forecast, program terminates, prerequisites note 96990, solution repair, source code, implemented
Related Notes : 
       
| 383823 | MP38: Restriction according to materials | 
| 378235 |