rlpr: 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/rlpr - from package: rlpr

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

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