[1]: https://i.sstatic.net/O9pQH.png
  [2]: https://i.sstatic.net/HF5BE.png

I am trying to create an enterprise geodatabase in oracle 11g, using the create enterprise geodatabase tool  in arcmap 10.2.
I have properly installed the oracle client needed and I am able to create a database connection (both as sys and system users).

However, when I am trying to execute the tool create enterprise geodatabase, it fails. 
I asks for administrator username and password as shown in the image.

![enter image description here][1]
![enter image description here][2]

Any ideas about how this could be resolved or debugged ?