prelude-admin: 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/prelude-admin - from package: libprelude2

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

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