dialog audio too low on Tivo Desktop recordings

I have Tivo Desktop Plus v2.8.3 running on my laptop with Windows XP. Playback of shows downloaded from my S3 have perfect sound on commercials, but during the shows, the dialog audio levels are super low while the "background" audio (laugh track, music, ambient sounds) are normal. I can't turn the volume up high enough to make the dialog discernible.

I've adjusted my laptop audio settings 9 ways from Sunday with no improvement. I tried the same show on my Windows 7 Desktop and the sound is fine. Is this a codec issue?

I ran ggieseke's TivoDesktopCodecMgr tool. The graph shows AC3 in to MainConcept Dolby Digital Audio Decoder, then to Tivo PCM Boost before going to Default DirectSound Device.

Is there a setting on my Tivo that needs to change?

Thanks for any assistance.

-Jerry