使用HTML2PDF类进行html到pdf的转换

I am trying to convert some html content to pdf using HTML2PDF class. But I am getting the below error

Fatal error: Uncaught ERROR n°4
File : /html2pdf/_class/parsingHtml.class.php
Line : 120

HTML code invalid, the tags are not closed in an orderly fashion.

Code I am using is below :

<?php
        require_once('html2pdf.class.php');
        $filename = 'test.html';
        $report=file_get_contents($filename);
        $content = '';
        $content .="<page  footer='page' backtop='20%' backbottom='13%' backleft='1%' backright='1%'>";
        $content .= $report;
        $content .="</page>";

        ob_get_clean();
        $pdf = new HTML2PDF('P','A4','en','true','UTF-8');
        $pdf->WriteHTML($content,false);
        ob_end_clean();
        $pdf->Output('Demographic_Analysis.pdf');
        exit;
?>

Please help