dompdf->render(); not working in api class - php

Question

I'm having a problem when trying to render html to pdf using dompdf.
I have the code placed inside a class and after the procedure code I would like it to create a pdf of the html.
This is the code I have at the moment:
$templatefile = file_get_contents("templates/costreport.htm");
//fill headers
$templatefile = str_replace("%DATES%",stripslashes($startdate)." - ".stripslashes($enddate),$templatefile);
if ($siteid>0) {
$pdfname = "costreport-".$clientid.".pdf";
} else {
$pdfname = "costreport-".$clientid."-".$siteid.".pdf";
}
//insert into database
//Close and output PDF document
$pdfname = str_replace("/","-",$pdfname);
$pdfname = str_replace("\\","-",$pdfname);
//create pdf
// unregister Yii's autoloader
spl_autoload_unregister('my_autoloader');
// register dompdf's autoloader
require_once("../system/dompdf/dompdf_config.inc.php");
// register Yii's autoloader again
spl_autoload_register('my_autoloader');
$dompdf = new DOMPDF();
$dompdf->set_paper("A4","portrait");
$dompdf->load_html($templatefile);
//set_time_limit(240);
$dompdf->render();
$pdf = $dompdf->output();
// You can now write $pdf to disk, store it in a database or stream it
// to the folder.
file_put_contents('../tmp/'.$clientid.'/'.$pdfname, $pdf);
The code fails when the dompdf->render(); is in but once I take that line out the code works and the file is created but I cant open it if it hasn't rendered.
I've tried debugging the code and made the template is HTML valid but I'm at a loss now.
The error I am getting back is just boolen false when I run the script with the dompdf->render(); in it.

Answer 1

The problem was that I had this piece of code at the top of my class.
/set up path to new dir including dir to be created
chdir("../tmp/");
$newdirpath = getcwd()."/".$clientid;
//if an old invoice ticket pack exists unlink it so as not to get things confused with the new pack being created.
if (file_exists(getcwd()."/$clientid_$siteid_CostReport.pdf")) {
unlink(getcwd()."/$clientid_$siteid_CostReport.pdf");
}
//setup temp dir
if (!is_dir($newdirpath)) {
//create new dir if it doesn't already exist!
mkdir($newdirpath);
} else {
//dir already exists we need to empty it out first incase there's old stuff in there we don't want to duplicate data
//$this->removedirectory($newdirpath,false);
}