umined: 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/umined - from package: xmined

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

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