That file looks good to me, according to those WHOTOs.
But you say still doesn't work properly
- one of the reasons I quit "Easy mode" and then xandros.
1] Something to check:
Does smplayer "/home/user/my documents/my videos/film.avi" &
play the file if you run it from a terminal? It should.
2] Try another way:
Take that command out of the file x-session-manager
and try following these
instructions for putting it in
Maybe that'll work better. You may need a sleep of more than 8 seconds, try it anyway.
3] Or yet another way:
instructions for installing the full KDE desktop and then use the
mechanism (instructions on the same page
as in  but further down)