Hi, I have an laptop running with Fedora 16 Lxde too. To solve this, I make a script which control backlight.
You can download my script at <
www.pgio.com.br/outros/slight.zip > (my website about Math).
If you open a terminal in the folder which you unzipped the 'slight.zip', as root, try this:
bash slight s 1 ---> to screen more dark
bash slight s 6 ---> to screen more bright, or any number between 0 and 7.
Together 'slight' is the 'mybattery' shell script.
The syntax is:
bash mybattery (don't need root)
If you want, open my scripts in a editor like gedit, vi, etc and you will understand how them work.