gnome-clocks: 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/gnome-clocks - from package: gnome-clocks

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

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