cw: 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/cw - from package: cw

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

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