Ubuntu – Acer aspire one d270 can not set brightness

I hope you can help me figure out how to set the brightness at my netbook.
Following problem appears since I installed ubuntu 11.10 on my acer:
I am not able to adjust the brightness by FN Keys nor manually at "systemsettings-display".
After searching with google for a while, I found a way via the terminal to adjust it with the folloqing command: "sudo setpci -s 00:02.0 f4.b=7f" ( from 00-9f).
That was a major breakthrough for me as I am still new to Linux OS.
But still seeking a way to get the FN keys for brightness to work, I kept searching until I found "askubuntu.com". I read through various Questions by other acer users and tried there solutions, but unfortunately none worked out for me.
From this thread:
fn + arrow keys don't adjust actual brightness on an Acer Aspire 5740
"sudo gedit /etc/X11/xorg.conf". This command did not work because the file was not found. I also used nano instead of gedit, but the file was empty( I think it just created the file since it did not exist).

These commands which i found gave me a boot loop and I had to repair ubuntu:
sudo gedit /etc/default/grub

Change the line GRUB_CMDLINE_LINUX="" into GRUB_CMDLINE_LINUX="acpi_osi=Linux"

sudo update-grub

From this post Screen Brightness not adjustable for Acer Aspire S3:

I tried the solution from the last post, but it did not work either.

Does anyone know what I could try?
I would appreciate it, if someone could help me out with this.

Thanks in advance

Netbook specs:

CPU: Intel Atom N2600
Memory: 2gb DDR3
Storage: 320 GB HD
GPU: Intel GMA 3600