sympa: 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/sympa - from package: sympa

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