thanks for your response. This is already set up. Just in my above message, the key is missing because I forgot to quote it here. The described problem persists even with the key included, i.e.
“/usr/bin/php /opt/dolibarr/scripts/cron/cron_run_jobs.php admin” (copypaste from Dolibarr settings page) leads to
“Dolibarr setup is not yet complete. install/index.php Click here to finish Dolibarr install process”
Alright, I had Dolibarr htdocs directory directly under /var/www/dolibarr, and the scripts folder I put somewhere else - I thought this would be fine. Now I put htdocs in /var/www/dolibarr/htdocs, changed Apache2 config and Dolibarr conf.php accordingly, copied the scripts folder to /var/www/dolibarr/scripts, and executed cron_run_jobs.php from there - now it works!
Maybe this should be made more clear in the documentation. Install docs say that it’s fine to place htdocs directly under /var/www/dolibarr, and the admin settings page says to run pathtoscript/scripts/cron/cron_run_jobs.php - which seems to suggest to me that this script could reside just anywhere.