psql

psql

Hi,
I am new to Unix systems.
I am getting the following error when trying to access the database
through psql:

$ psaql mydatabase
$ psql: can't load library 'libpq.so.3.0'

The psql was working fine until restarted the postmaster after setting
the configurations for tcp/ip to true in the postgreSQL.conf

Any help will be appreciated,
thanks in advance
beginner