nandtest: 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/sbin/nandtest - from package: mtd-utils

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

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