I am having problems with the audio/video sync when I export out of Premiere (CS3). I am working from a PC with 2gb ram and a 2.13GHz dual core processor.

The original file is an .avi -I am taking a section of this clip and exporting out (at the same frame rate) -through Adobe Media Encoder as a .mov file. Have been using the H264 codec for this.

I am not sure what is going on or what I may be doing wrong but when I export the audio is becoming out of sync (not a huge ammount but enough delay for me to notice and get irritated by)

All I am wanting got do it trim the clip so I can take it into After Effects and then apply motion graphics etc... over the top (the original clip in an hour long and i only want 3 min from it)

I can not work out why the audio is slightly out -all I am doing is trimming the clip and re-exporting it.

Does anyone have any advice/tips?