Server does not run post scripts


I am running UrBackup server from a Debian x64 based NAS. I have created post scripts to control when backup jobs has any errors to report it to my alerting system. I am talking about server scripts, not client scripts. I have this setup in a lot of NAS like this and it works fine, but, with this NAS for some reason it is not running post scripts. In the backup log I can´t see the call to the script when the backup has an error, so I suposed that UrBackup is not launching the script, but I don´t know why. Any suggestions?

Thank you so much.