Solution : https://service.sap.com/sap/support/notes/73584 (SAP Service marketplace login required)
Key words : 
additional key words cu50, import hot package sapkh31g09, material -> standard task list, master data list, incorrect header line, master data screen, screen saplcuko 2000, object change, program error, advance corrections
Related Notes : 
       
| 85237 | 3.1I:sales order entry change BOM -> task list | 
| 85236 | 3.1I:CU50 obj.depndncs display f.standard task list | 
| 82179 | 31I Display object dependencies in CU50 | 
| 73610 | 3.1H: CU50 'Multi-level task list configuration' |