mknod: 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:

/bin/mknod - from package: coreutils

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

On Debian possible default full paths are:

/bin/mknod - from package: coreutils
/usr/lib/klibc/bin/mknod - from package: klibc-utils

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

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