Frequent Disconnect in AMS Livestream HTTP Playback

Hi, I have been using Adobe Media Server 5, and lately I have issues on frequent disconnection of streaming playback.

The playback is running seamlessly until it abruptly stops, no "Buffering" indicator or whatsoever.

I am running the playback via HTTP. Network is OK.

Upon checking the logs, there is a message like:

[Wed Oct 23 23:19:07 2013] [info] Failed to read fragment from f4f file.
[Wed Oct 23 23:19:07 2013] [error] mod_f4fhttp [500]: Internal failure: Failed to read fragment from f4f file.

I tried googling it but I can't find any.

Can anyone please tell me what might be the problem?