mce-inject: 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/mce-inject - from package: ras-utils

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

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