As rjray mentioned, the webserver usually runs as user nobody, so all the cgi-script run as if they were executed by this user. If you need to open a file within a cgi-script, the file has to be readable by nobody.

You should also consider that files created by the cgi-script are owned by nobody with the permissions depending on his umask.

Note that these are some default configuration options. It's possible that the cgi-scripts are executed with the permissions and rights of the script-owner. Ask your admin about the webserver configuration and try to find a secure solution for your problem. The easiest way would be to change the file permissions to world-readable (chmod 666 <file>) which means that everyone may read the file who has access to the server - not a secure solution for sensible data ...

--
trust in bash
but tie your camel