The first response from Oracle Metalink was:
- Confirm it is physically a Linux OS and not any form of virtualisation (which is not supported)
In the meantime, I found the solution for this problem :-)
If you are running the Installer for the Oracle Fusion Middleware, you will be asked for either creating or extending a WebLogic Domain. Normally you choose to create a new Domain, which got the default name "ClassicDomain". If you choose this default name, you will receive the error "An internal operation has failed: The oracle instance is not empty. Select a different location or remove the instance at this location." if you change the Names for the Oracle AS Instance, the Instance Location aso.
So define your own WebLogic Domain Name and then you can also choose your own names for the Oracle AS Instance aso.