namebench: command not found

Have You tried accessing the binary with the full path?

Maybe Your $PATH variable doesn't contain the default paths? echo $PATH should give something like:

[root@server ~]# echo $PATH

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/namebench - from package: namebench

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