The open_basedir function defines the locations or paths from which PHP is allowed to access files using functions like fopen() and gzopen(). If a file is outside of the paths defined by open_basdir, PHP will refuse to open it.  You cannot use a symbolic link as a workaround, because the path that the symbolic link resolves to falls under the restrictions of the open_basedir function.

Note: The open_basedir restrictions can be turned off in the Apache configuration file, httpd.conf, with the following line: php_admin_value open_basedir none