html table - Dompdf fails on create output documents if tablecells contains rowspan -

if html document has cells tag rowspan, dompdf cannot create document. idea? thanks

<table> ...     <tr>         <td >                    marc conceptual metodol&ograve;gic         </td>         <td >25</td>         <td rowspan="2" >15</td>         <td rowspan="2" >15</td>         <td rowspan="3" >45</td>     </tr> ...