Any Help For AC3 Please =)

Hello =D

I was wondering if anyone out there who knows a lot about AC3 sound or AonE encodes can lend me a hand with a problem I have. I recently downloaded AonE's dvd version of Initial D 4th stage episode 1 and I noticed that around 30 and 36 seconds there is no sound in terms of vocals. When I opened up the file in media player I checked out what was going on with the AC3 codec and I saw that no sound was being ouput to the center channel. I changed output modes from 2/2 quadro to 3/1 4.1 surround and then to 4/1 5.1 surround. The strange thing was that even though sound was now being output to the center channel no vocals were heard. Can someone tell me if there is a problem with my codec, some settings, or maybe even the encode? I appreciate any help that comes my way and give my thanks in advance!