lcrack: 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/lcrack - from package: lcrack

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

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