Inquiry From Form [pgsql] - Mailing list pgsql-admin

i had postgresql installed with linux.
now iam unable to work with postgresql.i couls create a database, but when i issue pg_ctl -D <database location>
command,it is giving the following error: 
\"can\'t lock the file /tmp/.s.PGSQL.5432.lock:permission denied.\"
when issue any command, it is giving user \"myname\" not in system catalog,undefined.
please help me in this regard.