Hello,
Solved! 
I already solved the error! As I said before, in my previous message, I restarted the installation and in the oracle database screen, where it asks for the schema value, I inserted the SAPR3 schema instead of SAPSR3 and so with this change the installation finish without errors!
I will close this message but before I need to ask you one more thing if you don´t mind that is related with this new way to connect the SAP to the Oracle DB... tell me please if this is mandatory to do if I want to upgrade this Oracle DB from 11.2g to 12.1c! Because in software provisioning manager it inform the following:
"Database Schema Parameters The new default for ABAP Schema is SAPSR3. As of Oracle server version 12.1, ABAP SSFS is set automatically.".
So... this conversion from the "old connection method" (with SAPR3) to the "new connection method" (SSFS) is mandatory or not? And if so, we need to perform that conversion before the Oracle upgrade manually or it will do automatically?
Thank you,
Best regards,
João Dimas