wammu: 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/wammu - from package: wammu

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

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