These errors all mean something different and it is not clear from your description in what order they have occurred. The ORA-1092 error simply means that the Oracle instance was terminated abnormally. The ORA-1507 indicates that an 'alter database' statement was issued against a database that is not mounted. In your case, there was a command issued to 'alter database begin backup' but your database is not mounted.
Finally, the ORA-1519 indicates that a 'create database' statement failed while processing the named file. This error can occur under a number of different circumstances: one is that there is not enough disk space, and another possibility is that the SYS password contains special characters, such as "!" or "-", which are not allowed. Check that you have enough disk space to create the datafiles specified in your create database script. Also, if the SYS password contains special characters, change the password and re-run the create database command.
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