Can't install on redmine 2.3

[pydubreucq]

Hi,
I can't install this plugin, I va this error :
(in /usr/local/share/redmine)
rake aborted!
Could not copy /usr/local/share/redmine/plugins/redmine_dhtmlx_gantt/assets/javascripts/dhtmlxgantt.js to /usr/local/share/redmine/public/plugin_assets/redmine_dhtmlx_gantt/javascripts/dhtmlxgantt.js: Aucun fichier ou dossier de ce type - /usr/local/share/redmine/plugins/redmine_dhtmlx_gantt/assets/javascripts/dhtmlxgantt.js

root@redmine23:/usr/local/share/redmine/plugins# ls -l /usr/local/share/redmine/plugins/redmine_dhtmlx_gantt/assets/javascripts/dhtmlxgantt.js
lrwxrwxrwx 1 root root 58 9 avril 00:20 /usr/local/share/redmine/plugins/redmine_dhtmlx_gantt/assets/javascripts/dhtmlxgantt.js -> ../../../../dhtmlxGantt/dhtmlxGantt/sources/dhtmlxgantt.js

And ../../../../dhtmlxGantt/dhtmlxGantt/sources/dhtmlxgantt.js don't exist...
Do you have an idea please ?

Best Regards