aoe-mkdevs: command not found

Have You tried accessing the binary with the full path?

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/sbin/aoe-mkdevs - from package: aoetools

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

On Debian possible default full paths are:

/sbin/aoe-mkdevs - from package: aoetools

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