I'm unable to create a new database for the first time after installing postgres.app on my macbook pro

Anyone here can point me to the origin of the problem ?
I'm unable to create a new database for the first time after installing postgres.app on my macbook pro

Anyone here can point me to the origin of the problem ?
createdb is not a SQL statement, it's program for the command line (like psql or grep).
Inside psql you need to use the SQL statement CREATE DATABASE:
http://www.postgresql.org/docs/current/static/sql-createdatabase.html
And don't forget to terminate every SQL statement with a ; (if you had done that with createdb you would have gotten an error message immediately).