The first thing I would do it put your command into a script and run that rather than typing. it's much more efficient. You can run a script in sqlplus using:
Where "/path/to" is the real path substituted and script.sql is the name of your script.
The second thing I would do is generate the create database scripts using the DBCA, then compare your script to the generated script. That should give you an idea of where your script is wrong.
As I've said before, it is many years since Oracle recommended manually building databases rather than using the DBCA to generate them. You should probably ask your lecturer why he/she is asking you to do something that is not considered good practice.
Also, please stop putting "Please tell the step by step procedure to rectify the error". It's a sure fire way to piss anyone off on a forum. When people are helping you for free you can't demand any level of service. The manuals are available for free ans provide step by step instructions. If that is what you want I suggest you read them.http://docs.oracle.com/cd/E11882_01/ser ... m#BABEIAID