avidemux not getting sound
 

i have a series of flv videos and they all are pieces of one big video file i want to append them with avidemux but when i do the process
open file
select append and then select the following video
i did that like 8 times but only the first clip in the video has sound the rest are completely mute whats going on here

How about you demux all parts separately first, stitch only video stream together, same for audio and *then* put them in a container?