AVI is a wrapper format only, its not a method of encoding.  So the codec in use might be Xvid, DivX, MP4 or one of many others around. Being able to play one AVI file is no guarantee you can play another as it still might be using a different set of codecs.  Its entirely possible that your software will let you select the codec used somewhere.

There are a few programs out there that'll tell you the codecs video/audio files expect. I've never used any of them though.  I use VLC media player for playing stuff generally as it'll play pretty much anything you throw at it.  If you felt like installing that you can play the video file and then select View -> Stream and Media Info - > Advanced Information and that tells you the codecs in use by each stream.

Thats assuming of course your problem is codec related at all, seems likely but could be something else too.

I've no clue about the software you're using but the most likely cause of a problem like that is the codec being missing.  ie you have the appropriate video codec, the other people dont.
Do you have to use AVI? could try WMV or maybe MOV.