smuxi-server: 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-server - from package: smuxi-engine

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