dnsbulktest: 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/dnsbulktest - from package: pdns-tools

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

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