lxsession-xdg-autostart: 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/lxsession-xdg-autostart - from package: lxsession

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

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