The wizard detects an instance that actually doesn’t exist and that makes the installation fail.
2016-12-16 18:01:48,061  INFO List SSRS Instance from registry. Path:HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Microsoft SQL Server\Instance Names\RS
Result:[MSSQLSERVER, MSRS12.MSSQLSERVER];[HEATUAT, MSRS12.HEATUAT]
2016-12-16 18:01:48,273  INFO Load Selected Instance from local DB table ReportingStates. CurrentInstance:MSSQLSERVER2
2016-12-16 18:01:48,280  INFO Instantiated ReportingServer object. instanceName:MSSQLSERVER2
2016-12-16 18:01:48,322  ERROR Fail to connect Reporting Services namespace:root\microsoft\sqlserver\reportserver\rs_MSSQLSERVER2\v10\admin
System.Management.ManagementException: Invalid namespace
Renamed the file FRSConfig.sdf, therefore all old wrong references in the wizard were cancelled and able to properly configure reporting services.