Solution : https://service.sap.com/sap/support/notes/1178736 (SAP Service marketplace login required)
Key words : 
system issues error message gu 505, year-dependent fiscal year variant, fiscal year variant xy, missing fiscal year variant, fiscal year variant, fiscal year belonging, t009b-bdatj reason, attached program corrections, year-dependent, program error
Related Notes : 
       
| 1056150 | KS01: Cost center creation not possible | 
| 672255 | Shortened fiscal year/changing fiscal periods | 
| 531623 | KS133 unjustified when deleting a cost center |