There are plenty of avi threads already. The title of the thread is a bit confusing, but the OP is using a GoFlex Satellite Wifi harddrive. The avi file part is not an important part of the question.
I have a Go Flex Satellite wireless hard drive with avi format movies on it.
This WiFi harddrive works a bit different than a standard network drive, and as a result, there are not that many players that can actually connect to it.
Even if the files were in MP4 format, it is still the same.
The GoFlex, when it comes out of the box only has 3 ways of accessing files on it. The web-interface, a USB port and its own iOS (and Android) app.
While there are plenty of video player apps in the AppStore, there are none (to my knowledge) that are actually able to connect to the GoFlex. They offer support for smb/samba network shares, which is the common format, they offer support for ftp and a few other ways, but the GoFlex doesn't have those sharing methods, which makes it a bit tricky to play avi (or any other files) from it.
The GoFlex runs linux, which makes it possible to install additional methods on it. As I mentioned in my previous post, I modded my drive with smb on it, and then it can be accessed by other players.