|You don't have the correct codec installed to view it.|
An AVI format may not be the best choice for a PowerPoint presentation. AVI is just a container and could use one of a dozen different formats of video. Even if you got it working on your system, it would be hit or miss when you distribute it to others if that is your intent. I would suggest converting it to mpeg1 format. Pretty much every version of Windows (even back to Win98) will play mpeg1.
If you need a converter, try Super - http://www.erightsoft.com/SUPER.html