smd-server: 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/smd-server - from package: syncmaildir

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

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