cyr_userseen: 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_userseen - from package: cyrus-common

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

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