Can't play AVI files

If your're using Dapper Drake :

   * System -> Administration -> Synaptic Package Manager
    * To enable the extra Universe and Multiverse repositories
         1. Settings -> Repositories
         2. In the Installation Media tab, click Add. There are three separate repositories; Dapper Drake, Security Updates and Updates. Select each repository and check Officially supported, Restricted copyright, Community maintained (Universe) and Non-free (Multiverse). Ensure you click OK between each repository to save your changes
         3. You should now see those three repositories under Channels. Make sure Officially supported, Restricted copyright, Community maintained (Universe) and Non-free (Multiverse) appears under each repository

    * To add backports and PLF (new versions of many applications. Unsupported. May contain illegal packages. Use at own risk.)
         1. Settings -> Repositories
         2. Click on Add and then Custom
         3. Paste the following four lines into the box and click Add Repository, one line at a time:

deb http://archive.ubuntu.com/ubuntu dapper-backports main restricted universe multiverse
deb-src http://archive.ubuntu.com/ubuntu dapper-backports main restricted universe multiverse

deb http://packages.freecontrib.org/ubuntu/plf breezy free non-free
deb-src http://packages.freecontrib.org/ubuntu/plf breezy free non-free

Then open a terminal window and type the following one line at a time :

sudo apt-get install gstreamer0.10-ffmpeg
sudo apt-get install gstreamer0.10-gl
sudo apt-get install gstreamer0.10-plugins-base
sudo apt-get install gstreamer0.10-plugins-good
sudo apt-get install gstreamer0.10-plugins-bad
sudo apt-get install gstreamer0.10-plugins-bad-multiverse
sudo apt-get install gstreamer0.10-plugins-ugly
sudo apt-get install gstreamer0.10-plugins-ugly-multiverse

Thank you for help. I'm using breezy 5.10. Can I use this same steps?

For Breezy, change the backports to the following :

deb http://archive.ubuntu.com/ubuntu breezy-backports main restricted universe multiverse
deb-src http://archive.ubuntu.com/ubuntu breezy-backports main restricted universe multiverse

deb http://ubuntu-backports.mirrormax.net breezy-extras main restricted universe multiverse

deb http://packages.freecontrib.org/ubuntu/plf breezy free non-free
deb-src http://packages.freecontrib.org/ubuntu/plf breezy free non-free

And in the terminal windows use the following instead :

sudo apt-get install gstreamer0.8-plugins
sudo apt-get install gstreamer0.8-lame
sudo apt-get install gstreamer0.8-ffmpeg
sudo apt-get install lame
sudo apt-get install sox
sudo apt-get install ffmpeg
sudo apt-get install mjpegtools
sudo apt-get install vorbis-tools
sudo apt-get install w32codecs
gst-register-0.8

You can get alot more information here :

http://easylinux.info/wiki/Ubuntu

Thank you too much!