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 CentOS possible default full paths are:

/usr/bin/dtest - from package: dapl-utils

You may install the required package with command yum install {package}

On Debian possible default full paths are:

/usr/bin/dtest - from package: dapl2-utils

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

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