Hello @bidouilleur I think the problem may be caused by a virtual feed that no longer exists, but Im not sure. The line number of the error that you see does not match a line that I can see. You could try pulling in the latest emoncms:
cd /var/www/emoncms git pull
If that does not work, perhaps clearing redis:
and then reloading the page.
Assuming that you dont have any other applications using redis on the pi!