lnptest2: command not found

Have You tried accessing the binary with the full path?

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/lnptest2 - from package: lnpd

You may install the required package with command apt-get install {package}
Error in other languages:
lnptest2: bevel nie gevind nie
lnptest2: comandă negăsită
lnptest2: comando não encontrado
lnptest2: commande introuvable
lnptest2: command not found
lnptest2: käsku ei ole
lnptest2: không tìm thấy lệnh
lnptest2: komanda nerasta
lnptest2: Kommando nicht gefunden.
lnptest2: kommandot finns inte
lnptest2: komut yok
lnptest2: nie znaleziono polecenia
lnptest2: níor aimsíodh an t-ordú
lnptest2: no se encontró la orden
lnptest2: no s'ha trobat l'ordre
lnptest2: opdracht niet gevonden
lnptest2: parancs nem található
lnptest2: perintah tidak ditemukan
lnptest2: príkaz nenájdený
lnptest2: příkaz nenalezen
lnptest2: команда не найдена
lnptest2: командата не е открита
lnptest2: 命令找不到
lnptest2: コマンドが見つかりません