Server: Problem with loading Evernote file

Hi

I have some issue in apache log when trying to load notes exported from Evernote:
[Wed May 13 09:51:37.581789 2015] [:error] [pid 27565] [client a.b.c.d:49726] PHP Fatal error: Class 'OCA\OwnNote\Lib\DOMDocument' not found in /var/www/owncloud/apps/ownnote/lib/backend.php on line 46, referer: https://aa.bb.cc.dd/owncloud/index.php/apps/ownnote/

Thanks

Start with apps/ownnote/lib/backend.php at line 46 and reproduce loading an Evernote-exported note while reviewing the reported Apache/PHP fatal error. Trace how the Evernote file is parsed and determine what is required for the load to complete without the reported class-not-found failure. Done means the exported note loads successfully without that fatal error.

Written by the indexing model from the issue text.