cyr_expire: 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/cyr_expire - from package: cyrus-common

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

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