Error creating a new database in Oracle 10g

I am getting an error when I try to create a fresh database using "create database command".

I am getting database already mounted error.

Any ideas, what should I do?

probably your oracle database user does not have the correct privileges for creating a database.
most DBA will create a user account to access the schema, such as the application, separate from the administrative user that is required for creating databases.

In some cases the application's user account is even restricted from creating or dropping tables.

Maybe contact your DBA and have them create the database for you, or have them grant you the create database privilege

Are you actually trying to create a databse?
Follow the steps here.

Second, this is a Java forum and this question is an Oracle question, so you might want to take it to OTN (the Oracle forums).

Finally, are you sure you're creating a database? And you don't simply want to create a new schema?