syncmail: 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/syncmail - from package: cvs-syncmail

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

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