Problem in Postgresql installation

Hi=20

I have installed a 7.1.3 postgresql version on my linux server. (RedHat 7.2)
=20
When I type "createuser xxxxxxxx" it asks me :  Shall the new user allowed =
to create databases (y/n)?=20
                                                                        Sha=
ll the new user allowed to create more new user (y/n)?=20

I answer yes to the both questions and then a bug report said :=20
    " psql : connetDbstart()  -- connect() failed - no such file or directo=
ry
     Is the postmaster running locally and accepting connections on Unix so=
cket :'/tmp/.s.PSQL.5432'=20
   createuser : creation of user 'xxxxxxx' failed.

I already had answers to this but I am a newbie in linux, so i didn't under=
stand what i have to do exactly to resolve this problem.

Someone wrote me :=20
1. Did you initialized your database with initdb ?
2. Have you started Postgres with postmaster -i   or pg_ctl start ?
3. Have you modified parameters in $PGDATA/postgresql.conf file ?
Follow your answers, you have solved your problem
=20
1.When i type initdb it said me that it's not possible to create specific d=
irectories (pgsql and data)
2. How am I supposed to use the postmaster or pg_ctl ??
3. The installation is not complete so i haven't a postgresql.conf file ....

Thanks for your help.
Mr Paquin