dateutils.dtest: 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/dateutils.dtest - from package: dateutils

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

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