We are using the latest build of LSWS 4.1 RC3 as of 09.01.2010 and have tried to set up MP4 streaming. The mime types have been added correctly, the MP4 files have the moov atom at the beginning and we have tried both JWPlayer and FlowPlayer and they both give the same result:
They will play the video but when you try to seek, a message appears stating that it cannot find the video file:
200, Stream not found, NetStream.Play.StreamNotFound, clip: '[Clip] 'video/intro_cam.mp4'
Video not found: cam_intro.mp4
The video is there and is playable because it starts playing before you try to skip ahead.