sms_address: 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/sms_address - from package: smsclient

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

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