smart-notifier: command not found

Have You tried accessing the binary with the full path?

Maybe Your $PATH variable doesn't contain the default paths? echo $PATH should give something like:

[root@server ~]# echo $PATH
/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin:/root/bin

If it's empty, You may set the PATH variable with this command

export PATH="/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin:/root/bin"

On Debian possible default full paths are:

/usr/bin/smart-notifier - from package: smart-notifier

You may install the required package with command apt-get install {package}
Error in other languages:
smart-notifier: bevel nie gevind nie
smart-notifier: comandă negăsită
smart-notifier: comando não encontrado
smart-notifier: commande introuvable
smart-notifier: command not found
smart-notifier: käsku ei ole
smart-notifier: không tìm thấy lệnh
smart-notifier: komanda nerasta
smart-notifier: Kommando nicht gefunden.
smart-notifier: kommandot finns inte
smart-notifier: komut yok
smart-notifier: nie znaleziono polecenia
smart-notifier: níor aimsíodh an t-ordú
smart-notifier: no se encontró la orden
smart-notifier: no s'ha trobat l'ordre
smart-notifier: opdracht niet gevonden
smart-notifier: parancs nem található
smart-notifier: perintah tidak ditemukan
smart-notifier: príkaz nenájdený
smart-notifier: příkaz nenalezen
smart-notifier: команда не найдена
smart-notifier: командата не е открита
smart-notifier: 命令找不到
smart-notifier: コマンドが見つかりません