rlpq: 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/rlpq - from package: rlpr

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

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