lbt2dot: 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/lbt2dot - from package: lbt

You may install the required package with command apt-get install {package}
Error in other languages:
lbt2dot: bevel nie gevind nie
lbt2dot: comandă negăsită
lbt2dot: comando não encontrado
lbt2dot: commande introuvable
lbt2dot: command not found
lbt2dot: käsku ei ole
lbt2dot: không tìm thấy lệnh
lbt2dot: komanda nerasta
lbt2dot: Kommando nicht gefunden.
lbt2dot: kommandot finns inte
lbt2dot: komut yok
lbt2dot: nie znaleziono polecenia
lbt2dot: níor aimsíodh an t-ordú
lbt2dot: no se encontró la orden
lbt2dot: no s'ha trobat l'ordre
lbt2dot: opdracht niet gevonden
lbt2dot: parancs nem található
lbt2dot: perintah tidak ditemukan
lbt2dot: príkaz nenájdený
lbt2dot: příkaz nenalezen
lbt2dot: команда не найдена
lbt2dot: командата не е открита
lbt2dot: 命令找不到
lbt2dot: コマンドが見つかりません