can't connect to postmaster or postgresql server

i'm new to linux. i started the postgresql 7.4 server
in the root using red hat 9 and it says that
Postmaster already running. but when i used QT
Designer's database connection, in which i wrote
Driver: QPSQL7 database: all user: all, host:
localhost a dialog box appears stating: can not
connect to the database. please ensure that the
database is running and that all the connection
information is correct. [QPSQL: unable to connect
could not connect to server. connection refused. is
the server running on host localhost and accepting
TCP/IP connections on port 5432?

i tried to open the pg_hba.conf and postgresql.conf to
change the tcp/ip from false to true still the problem
persists.

prior to this, when i used $ postmaster -D
/var/lib/pgsql/data, the following message is posted
FATAL: cannot open /var/lib/pgsql/data/PG_VERSION:
Permission denied.

sometime when i type service postgresql start in the
root the following message is posted:
bash: service: command not found

itried to loggin as posgres user and used bash-2.05b$
service postgresql start the same message is posted.
bash: service: command not found

However, i followed the tutorial below and i got it
correct:

Login as user postgres: su - postgres

Initialize PostgreSQL database server:
/usr/bin/pg_ctl -D /var/lib/pgsql/data -p
/usr/bin/postmaster -l logfile start &

Create a database: createdb bedrock
(As Linux user postgres)
Connect to the database: psql bedrock
Execute command as Linux user postgres
You will now be at the PostgreSQL command line prompt.

bedrock=# \c bedrock
You are now connected to database bedrock.
bedrock=# create table employee (Name char(20),Dept
char(20),jobTitle char(20));
CREATE
bedrock=# INSERT INTO employee VALUES ('Fred
Flinstone','Quarry Worker','Rock Digger');
INSERT 18733 1
bedrock=# INSERT INTO employee VALUES ('Wilma
Flinstone','Finance','Analyst');
bedrock=# INSERT into employee values ('Barney
Rubble','Sales','Neighbor');
bedrock=# INSERT INTO employee VALUES ('Betty
Rubble','IT','Neighbor');
bedrock=# SELECT * from employee;

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