I suspect that you are running into a pathing problem because the include files are in different directories doing relative references.
The way I usually solve this is to create one global.php file with the following in it:
$hostRoot = $SERVER["HTTP_HOST"];
if ($hostRoot == "localhost")
$hostRoot = "http://localhost";
$docRoot = $SERVER["DOCUMENT_ROOT"];
$imageRoot = $hostRoot . "/Images/";
Then I require_once the global.php in all of my files:
require_once("global.php");
Every image reference is done as so in the markup:
<img src=\"$imageRoot . "myImage.gif"\">
Hope this makes sense