There is a problem with the links on your site. The following screenshot will reveal the problem - it is an extra full stop at the end of the link.
By copy/pasting the link (without the full stop) into my browser I was able to open and view the videos.
Regarding file formats for web sharing I tend to use the settings adopted by You Tube
You Tube Website wrote:
We recommend the following settings:
* MPEG4 (Divx, Xvid) format
* 320x240 resolution
* MP3 audio
* 30 frames per second
Resizing your video to these specifications before uploading will help your videos look better on YouTube.
To make things easier, I create a profile in my VideoEditor
VideoStudio = Tools | Make Movie Manager
MediaStudio = Create Template - this can be done at the time of opening the MediaStudio program