lptest: 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/lptest - from package: lpr

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

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