lo_import permissions problem

I have been trying to import a file into a table using lo_import and keep
getting the error

ERROR: could not open server file "/tmp/myfile": Permission denied

The file is in /tmp so it is world readable and I made sure the file had the
correct permissions by doing chmod 777. My user has super user privileges as
well. I tried importing other files such as /etc/hosts as a test and this
worked fine. I am running Gentoo linux with Postgres 8.0. Does anyone have
any idea what the problem is and what I need to do to correct it?

Thanks in advance