asmail: 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/asmail - from package: asmail

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

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