mc: 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:

/usr/bin/mc - from package: mc

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

On Debian possible default full paths are:

/usr/bin/mc - from package: mc

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

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