smd-pull: 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
/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-pull - from package: syncmaildir

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