hi dave, actually those ogv is not really important, the most important is you can encode it right.
you can try this video : http://jegtheme.com/asset/jkreativ/video/newbali.mp4
and this : http://jegtheme.com/asset/jkreativ/video/newbali.webm
and see if its work on your end. if its work, and it must be something wrong with your video encoding.