lt: 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/lt - from package: looptools

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

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