Solution : https://service.sap.com/sap/support/notes/821772 (SAP Service marketplace login required)
Key words : 
sapbwnews bw sp12 netweaver'04 stack 12, 0b            import support package 27, 10 content            import support package 21, form rgc_plegen_m-01- occurs, 50            import support package 12, 0b support package 27, solution bw 3, support package, sapbwnews bw3, 1 content sp 21
Related Notes : 
       
| 985882 | X299 BRAIN in SAPLRRK0; form SETXX_FUELLEN_15-02- | 
| 894561 | x299 Brain in SAPLRRK0; Form RGC_PLEGEN_M-02- | 
| 869488 | x299 Brain in SAPLRRK0; form SETXX_FUELLEN_15-01- | 
| 867326 | X299 Brain in prog SAPLRRK0 and form SETXX_fuellen_15-01- | 
| 856562 | X299 Brain in Saplrrk0; Form SETXX_FUELLEN_15-02- | 
| 804214 | |
| 763340 | SAPBWNews BW Support Package 12 NetWeaver'04 Stack 12 RIN | 
| 723263 | SAPBWNews BW 3.1 Content Support Package 21 | 
| 723258 | SAPBWNews BW 3.0B Support Package 27 |