lxsession-edit: 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/lxsession-edit - from package: lxsession

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