PHP: Cannot instantiate non-existent class

So I have FCKEditor installed on my site. I ran the test that shows the samples and it worked. When I am trying to put it on a page, however, I get Fatal error: Cannot instantiate non-existent class: fckeditor on line 103. I know I have the file paths right and I have been checking but I cannot find anything else that I am doing wrong. Any help would be appreciated.

<?php
include_once("/Test/AdminTool/FCKEditor/fckeditor.php");
?>


       <?php
      This is line 103------>$oFCKeditor = new FCKeditor('PageEdit') ;
         $oFCKeditor->BasePath = '/FCKEditor/' ;
         $oFCKeditor->Value = '<p>This is some <strong>sample text</strong>. You are using <a href="http://www.fckeditor.net/">FCKeditor</a>.</p>' ;
         $oFCKeditor->Create() ;
      ?>