lsftp: 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/lsftp - from package: lsh-client

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