No sound with someone REC with Dvico USB (1 Viewer)

[CCN]

MediaPortal Version: 0.2.0.4
Windows Version: XP Pro SP2
CPU Type:
HDD:
Memory:
Motherboard:
Motherboard Chipset:
Motherboard Bios:
Video Card:
Video Card Driver:
Sound Card:
Sound Card AC3:
Sound Card Driver:
1. TV Card: Dvico USB FUSION
1. TV Card Type:
1. TV Card Driver: Last
2. TV Card:
2. TV Card Type:
2. TV Card Driver:
3. TV Card:
3. TV Card Type:
3. TV Card Driver:
4. TV Card:
4. TV Card Type:
4. TV Card Driver:
MPEG2 Video Codec: intervideo windvd
MPEG2 Audio Codec: intervideo windvd
Satelite/CableTV Provider:
HTPC Case:
Cooling:
Power Supply:
Remote:
TV:
TV - HTPC Connection:

I m using media portal, with one tuner : Dvico Fusion Gold USB.
When i m doing a record with Winfast (my latest prog) everything is all right.
But, with MP it s another thing. I'm programmed records (with EPG or manually) but someone records do not have sound. The file is correct size, correct format.
At the correct time, the channel is changing, the logo REC is coming. but one time to 2 there is no sound.
i m search on any forum in france, but no solution.... i'm loose

thnks for my poor english.