Problem to export to PDF

Hi all.
I have a problem during export to a pdf.
I post last row of error_report:

<event week='undefined' day='1' type='event' x='102' y='1342.063492063492' width='97.21428571428572' height='50.3968253968254'><header><![CDATA[<b>Annabella</b>&nbsp;&nbsp;21:25--21:55]]></header><body color='rgb(255, 231, 99)'><![CDATA[<b>Pasta,,,,</b><br>Riso,,,]]></body></event></data>
I have a blank page.
Can you help me?