sieveeditor: 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/sieveeditor - from package: kmail

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

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