html video file not found

I have made a couple of simple MOV files that I would like to insert into a wordpress posting.
After reading your ads, which state that I could play mp4 videos, I downloaded your player.
I then made various MP4 versions of the video files (various bit rates, etc) using the export command in QuickTime pro. All of these work in either QuickTime or in Windows Media Player
On the installation you say I should find some java script for old Explorer browsers but I assume that this is irrelevant to my problem. Everything else in the installation seems ok.
I insert the movie into the post. Sure enough there is a black screen in the preview. At the top it gives some “video warnings.” Often these are comments on the bit rate being too low, etc. The most important comment seems to be that I am using an MP4V codec and that I should use H264 instead.
If I try to play the video it shows nothing except “html: video file not found.”
Any suggestions or should i just give up on your player? If I get a license would anything be easier?
I am not a sophisticated programmer. However I am not completely innocent :)
Thanks for any suggestions
Terry