Hi Lara,
I did a quick test and I can confirm the problem. My Apache log shows the following error message:
[Thu Jul 13 18:29:41.246577 2017] [:error] [pid 2967] [client 127.0.0.1:43704] PHP Fatal error: 'break' not in the 'loop' or 'switch' context in /home/lars/public-html/dokuwiki/lib/plugins/dw2pdf/mpdf/classes/svg.php on line 2710, referer: http://localhost/doku.php?id=testseite_switchpanel
So unfortunately there is a bug in the dw2pdf plugin. To be more precise in the mpdf software which the plugging is using. You should open an error report in the plugins issue tracker at
https://github.com/splitbrain/dokuwiki-plugin-dw2pdf/issues/.
P.S.: not sure if it helps but the ODT plugin works together with the switchpanel plugin to and you could also export to PDF if LibreOffice is installed on the server. But the output between dw2pdf and ODT can have big differences so you would need to test if it meets your requirements.
Best Regards,
Lars