gworldclock: 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/gworldclock - from package: gworldclock

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

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