summarise-mailbox-preserving-privacy: 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/summarise-mailbox-preserving-privacy - from package: chiark-scripts

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

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