permissions failure to copy csv data

Readers,

The following command was entered from normal user account where csv files are:

COPY newdatabasenametable FROM '/path/to/file.csv' WITH CSV;
ERROR:  could not open file "/path/to/file.csv" for reading: Permission denied

Superuser X created by linux root account but unable to read csv files
even though permissions are read-execute for others (tried to change
to read-write-execute, no success):

su root
su postgres
createuser X
createdb -U X newdatabasename

When changing to postgres account:

pwd: /path/to/

su root
su postgres
psql newdatabasename
could not change directory to "/path/to
Welcome to psql 8.2.13, the PostgreSQL interactive terminal.

Type:  \copyright for distribution terms
       \h for help with SQL commands
       \? for help with psql commands
       \g or terminate with semicolon to execute query
       \q to quit

How do I configure the permissions correctly?

Yours,

postgresql@conference.jabber.org
postgresql8213
mandriva2008