train-kytea: 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 Debian possible default full paths are:

/usr/bin/train-kytea - from package: kytea

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

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