clocktest: 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/lib/plainbox-providers-1/checkbox/bin/clocktest - from package: plainbox-provider-checkbox

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

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