partprobe: 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:

/sbin/partprobe - from package: parted

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

On Debian possible default full paths are:

/sbin/partprobe - from package: parted

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

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