cmew: 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/cmew - from package: mew-beta-bin
/usr/bin/cmew - from package: mew-bin

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

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