kni_burnintest: 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/kni_burnintest - from package: libkni3-examples

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

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