burnP6: 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/burnP6 - from package: cpuburn

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

Error in other languages:
burnP6: bevel nie gevind nie
burnP6: comandă negăsită
burnP6: comando não encontrado
burnP6: commande introuvable
burnP6: command not found
burnP6: käsku ei ole
burnP6: không tìm thấy lệnh
burnP6: komanda nerasta
burnP6: Kommando nicht gefunden.
burnP6: kommandot finns inte
burnP6: komut yok
burnP6: nie znaleziono polecenia
burnP6: níor aimsíodh an t-ordú
burnP6: no se encontró la orden
burnP6: no s'ha trobat l'ordre
burnP6: opdracht niet gevonden
burnP6: parancs nem található
burnP6: perintah tidak ditemukan
burnP6: príkaz nenájdený
burnP6: příkaz nenalezen
burnP6: команда не найдена
burnP6: командата не е открита
burnP6: 命令找不到
burnP6: コマンドが見つかりません