smstrade_send: command not found

Have You tried accessing the binary with the full path?

Maybe Your $PATH variable doesn't contain the default paths? echo $PATH should give something like:

[root@server ~]# echo $PATH

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/smstrade_send - from package: python-smstrade

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