I already try chmod 777 to my /home/$USER/.fluxbox/startup but it does not startup the program. But if I reset the permission for startup file to default and start fluxbox in GUI login. The startup work fine.
If you've already switched to /home/$USER/.fluxbox directory and issued the command "chmod +x startup" it should be good to go.
The VL 5.8 package for fluxbox 1.0rc3 contains the following line:
exec fluxbox
The startup file in my /home/$USER/.fluxbox directory reads:
# fluxbox startup-script:
#
# Lines starting with a '#' are ignored.
# You can set your favourite wallpaper here if you don't want
# to do it from your style.
#
# fbsetbg -f /home/vl1/wallpapers/orange-chaos.jpg
#
# This sets a black background
/usr/X11R6/bin/fbsetroot -solid black
# This shows the fluxbox-splash-screen
# fbsetbg -C /usr/X11R6/share/fluxbox/splash.jpg
# Other examples. Check man xset for details.
#
# Turn off beeps:
# xset -b
#
# Increase the keyboard repeat-rate:
# xset r rate 195 35
#
# Your own fonts-dir:
# xset +fp "/home/vl1/.fonts"
#
# Your favourite mouse cursor:
# xsetroot -cursor_name right_ptr
#
# Change your keymap:
# xmodmap "/home/vl1/.Xmodmap"
# Applications you want to run with fluxbox.
# MAKE SURE THAT APPS THAT KEEP RUNNING HAVE AN ''&'' AT THE END.
#
# unclutter -idle 2 &
# wmnd &
# wmsmixer -w &
xfce-mcs-manager &
rox -p desktop &
# And last but not least we start fluxbox.
# Because it is the last app you have to run it with ''exec'' before it.
exec /usr/X11R6/bin/fluxbox
# or if you want to keep a log:
# exec /usr/X11R6/bin/fluxbox -log "/home/vl1/.fluxbox/log"
As you can see this file will cause the same apps to start with fluxbox whether the user logs in from command line or from GUI Login.
the menu setting for fluxbox is simple.......I have done it my own..Smiley
It is pretty simple. I only mentioned it because I was not sure if I had read your post correctly and I wanted to give a thorough response.

Happy Vectoring!