Streaming vid skips after buffering

Hi guys

Am pretty new to scripting and Flash and streaming vid is proving a massive headache at the mo. Have bashed through most of my problems but this one has got me stumped, scripting skills not up to the task.

When my streaming videos start they will buffer and begin to play as normal. However, as soon as the vid starts buffering again a problem arises. Basically what is happening is that Flash is buffering the video to a certain point, but instead of resuming playback from the point where the vid paused it now jumps instantly to the end of the newly buffered area without playing the vid portion in between. Which essentially means that it skips merrily through the video and never stops buffering. Why is it doing this???

Im sure it can be hacked and any suggestions in this direction would be most welcome. That said i'd prefer to get to the root of the prob, particularly if this is a codec/keyframe issue, since i could then re-export the vids appropriately.
Thanks for any help!

Am using mpg4 (.mov) with H264 compression and keyframes at 1 sec intervals