BasePath Problem - Editor Not Showing Up

I never had a problem using fckeditor on my server but now it's on a testing server owned by the client. I can't seem to get the fckeditor to show up. I'm including the php file:

<?php require_once("fckeditor/fckeditor.php"); ?>

When I run this:

<?php echo "path:" . $_SERVER['DOCUMENT_ROOT']; ?>

I get "D:\www\test.domainname.com"

The php file calling the editor and the fckeditor folder is in /www/test.domainname.com and i'm initializing with this code:

$oFCKeditor = new FCKeditor('content');
$oFCKeditor->BasePath = '/fckeditor/';
$oFCKeditor->Create();

When I run the page the iframe shows "The page cannot be found." I checked the source of the main page and the iframe has src="/fckeditor/editor/fckeditor.html?InstanceName=content&Toolbar=Default" which should be correct. But when I open the iframe in a new window the url is "http://###.##.#.###/test.domainname.com/www/fckeditor/editor/fckeditor.html?InstanceName=content&Toolbar=Default" ( its adding the xtra test.domainname.com/www part)

Any ideas how to get this working? I've tried changing the BasePath to everything you can imagine including the full "http://...." address but the url in the iframe when I open it in a new window is the same. If I copy the iframe html and manually put it in, the editor shows up:

<iframe id="content___Frame" src="/fckeditor/editor/fckeditor.html?InstanceName=content&amp;Toolbar=Default" width="100%" height="200" frameborder="0" scrolling="no"></iframe>

Help is appreciated!