knotes-migrator: 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/knotes-migrator - from package: kdepim-runtime

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

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