wmclockmon-cal: 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/wmclockmon-cal - from package: wmclockmon

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

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