knn-landscape: 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/knn-landscape - from package: python-mlpy

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

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