Solution : https://service.sap.com/sap/support/notes/1548963 (SAP Service marketplace login required)
Key words : 
onfiguration - system landscape - landscape, role generation occurs based, configuration - system landscape - landscape, step stays yellow, enterprise role management, enterprise role manager, systems role generation, role generation system, systems risk analysis, conduct risk analysis
Related Notes : 
       
| 1603475 | Risk Analysis Failed in Role Generation | 
| 1527660 | Role Generation Fails in 702 Basis Plug-in(RTA) System. | 
| 1504762 | Error in Role Generation in ERM | 
| 1502881 | Illegal Characters Error in Role Generation | 
| 1485227 | Error in generating roles with Area Menus | 
| 1168183 | Enterprise Role Management 5.3 Support Package (VIRRE) | 
| 1147651 | RE Role generation : Unable to interpret * as a number |