can't access postgresql database

[Lubna89]

i have installed a software on ubuntu 10.10 that contains postgres inside it, and postgres was automatically installed with software .run file.

now the database directory is inside the /opt directory and every time i try to access it i have the error message:

couldn't change directory to root
psql: couldn't connect to server: no such file or directory
is the server running locally and accepting
connection on unix domain socket "/var/run/postgersql/.s.PGSQL.5432"?

[Lubna89]

hey,
for those who may have the same problem, i'v tried:
psql -h localhost -U postgres
and it worked.