cinnamon-settings-users: command not found

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/cinnamon-settings-users - from package: cinnamon

You may install the required package with command apt-get install {package}

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