ctl_mboxlist: 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/lib/cyrus/bin/ctl_mboxlist - from package: cyrus-common

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

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