phpinfo() and ini_get() report that include_path is set to ".:/usr/local/lib/php". However, include "filename" and fopen(filename, mode, "1") fail to access files in /usr/local/lib/php. Manually editing php.ini to explicitly include the default value for include_path resolves the problem.

Test script:
<?php
phpinfo();
$path = ini_get("include_path");
include("test.txt");
$fh = fopen("test.txt", "r", 1);
?>

Revised php.ini:
;include_path   =                   ; UNIX: "/path1:/path2"  Windows: "\path1;\path2"
include_path    =  ".:/usr/local/lib/php"