When creating H.264 Flash video* for displaying in browser using player like JW FLV Media Player ( http://www.longtailvideo.com/players/jw-flv-player/ ), the MOOV atom need to be at the beginning of the file, not the end. Otherwise, the whole MPEG-4 file need to be downloaded before start playing, instead of starts immediately with http pseudo streaming.
export the MP4 file that way.
If the file is small (like < 1GB, otherwise you may get #1000 & 2029 errors), you can use utility like QT Index Swapper ( http://renaun.com/blog/2007/08/22/234/ ) to fix it.
* for "Moviestar" Flash 9 update 3 (v 220.127.116.11) 2007/12/03 or above.
** 1920x1080 Level 4.2 MPEG-4 from AME does not play correctly in Playstation 3 also. The dreadful 80028801 error.
CVS Pro X2
QT Index Swapper