include function partially not working w/o modifications
===

**BACKGROUND**
Recently we upgraded our web server (PHP 5.3.3) by replacing it with a new server (PHP 5.3.3) and at least one of the include functions stopped working. 

Following a response on this site I changed the include function from "include('requested_page');" to "getcwd()."/".$_SESSION['requested_page'];" and that fixed the issue. 

getcwd() returns "var/lib/vhost/httpdocs/<domanin name><current folder>

**QUESTION**

Is there a setting in php.ini (or else where) that needs to be changed to allow the include function to work w/o adding getcwd()?


**INFO:**
Old server: Centos 5, new server Centos 6, both servers are running PHP 5.3.3 and Plesk 11

Thanks