dclock: 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/dclock - from package: dclock
/usr/bin/dclock - from package: ivtools-bin

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

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