I ran test the test application and can confirm that this bug occurs in Windows Vista RTM. I was tipped off by a reader about some problems with AVI files in Windows Vista, based on this MSDN forum link: With this codec on your computer, you will have fixed MP4 errors when playing them on Windows Media player.♪VIFile library in Windows Vista creates invalid AVI files It is free to download and easy to install. The best way to get windows media codec is to download it from Microsoft’s official website. By now the MP4 file should play smoothly. After installing the codec, you can re-launch the Windows Media player and play the MP4 file. Complete the process by following the prompts on the screen. Alternatively, you opt to “Run the program from its original location.” You can also save the codec if you want to install it later on your computer.

Once you have downloaded the codec, go to downloads and “Open” the codec. If it fails to download within 30 seconds, there is a link provided that allows you to download and install the codec manually. Click on it, and the codec will be downloaded immediately. Next, you will see a red button indicated, “Download” on the Codec Installation package. Open your browser and paste this URL that lands you to Microsoft official website codec download. We have made things easier for you by providing a step by step guide on how you install and download Windows Media Codecs from the Official Windows Site. A workable solution to this issue is to download MP4 codec windows from Microsoft's official website. You will notice that when you try to play the same video with other media players, it works well but with Windows Media player it will either fail to play, or the audio might not be good, or the audio and video may fail to synchronize. With the Windows Media player, you can face difficulties or errors when playing MP4 media player.

How to open avi files on vista