Cannot redeclare class Doku_Plugin_Controller

[simonpa71]

This error appears when I try to install the plugin on Hogfather, just upgraded from Greebo.
I had to disable all the plugins before running down this one that provoked a Fatal Error.
Tried uninstalling and re-installing the plugin, to no avail.
The full error is:
Cannot redeclare class Doku_Plugin_Controller in /web/htdocs/www.mydoku.no/home/doku/inc/deprecated.php on line 348

The doku is not running on a regular server, but on a "Hosted Linux".
Wiki Collect Data gives some info about the environment:
os Linux
webserver Apache
php_version 5.6.32
php_sapi cgi-fcgi
php_memory 268435456
php_exectime 300

Is there anything else I can upload to assist in debugging?

[gamma]

Did you install the lastest version of the plugin?

[simonpa71]

plugin.info.txt says:
base siteexport
author i-net software
email [email protected]
date 2020-08-28
name Site Export
desc exports the dokuwiki site in the given format
url https://www.dokuwiki.org/plugin:siteexport

I have also tried upgrading PHP to
php_7.1.33

[simonpa71]

After upgrading the dw2pdf plugin, this site export plugin does not block dw with Fatal Error
https://www.dokuwiki.org/plugin:dw2pdf
Last updated on 2020-11-12