Class "html" not found in rcube_api.php line 447

[sipiatti]

Hi All,

I did a fresh install with the latest stable roundcube (0.9.5).
After installation I got this in log/errorrs:
[29-Jan-2014 11:04:48 UTC] PHP Fatal error:  Class 'html' not found in /usr/share/nginx/www/webmail/program/lib/Roundcube/rcube_plugin_api.php on line 447

the html.php with class 'html' exists in the lib/Roundcube directory.
What could be the problem?