smuxi-frontend-stfl: 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/smuxi-frontend-stfl - from package: smuxi-frontend-stfl

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