Solution : https://service.sap.com/sap/support/notes/665125 (SAP Service marketplace login required)
Key words : 
error total / mad <= tracking limit, relative error = error / historical, rule minimum mad, function module forecast, automatic model selection, parameter optimization tests, program error, historical values, relative errors, model selection
Related Notes : 
       
| 932258 | Forecast: Problem in the parameter optimization | 
| 733442 | Forecast: Short dump COMPUTE_FLOAT_ZERODIVIDE | 
| 719900 | Forecast: Model selection procedure 2 incorrect | 
| 610612 | Forecast: initialization during model selection | 
| 183779 | Matl forecst:Incor.modl selctd f.modl sel.procdre 2 |