U-Mix 44 work then stop

Hi,
I've just recieved my U-Mix 44 and its having a weird behaviour.
Sometimes it run perfectly some other times its really unstable.
First of all my config:
Laptop
Intel Core i7 Q720 (8x 1,6GHz)
4Go DDR2 Memory
IDT HD Audio built-in soundcard (5.1)
Windows 7 64bits
VDJ 6
The troubles:
I have crackles on both output while using Virtual DJ 6 with vinyl timecode setup, MixVibesAsioUMix44 audio driver selected. After a short moment of smooth running it stops, no more timecode signal.
Unplug and plug it back doesn't fix the probleme. I hear the usb plug-in/plug-out windows sound without touching the soundcard usb plug when it becomes unstable with only u-mix44 plugged-in.
I tryed multiple usb ports, rebooting the laptop, reinstall both asio and mixvibes driver, and made sure of no usb power managing.
I'm thinking of some compatibility issues with my built-in sound card wich is 5.1 emulated (IDT HD Audio).
From Asio control panel the u-mix44 is not listed as a device, and from window's devices control panel u-mix44 use a microsoft driver but I find no way to make windows use the mixvibes driver.
Hope I gave enough details and one of you will be able to help me fix this.
Thank you ^^
I've just recieved my U-Mix 44 and its having a weird behaviour.
Sometimes it run perfectly some other times its really unstable.
First of all my config:
Laptop
Intel Core i7 Q720 (8x 1,6GHz)
4Go DDR2 Memory
IDT HD Audio built-in soundcard (5.1)
Windows 7 64bits
VDJ 6
The troubles:
I have crackles on both output while using Virtual DJ 6 with vinyl timecode setup, MixVibesAsioUMix44 audio driver selected. After a short moment of smooth running it stops, no more timecode signal.
Unplug and plug it back doesn't fix the probleme. I hear the usb plug-in/plug-out windows sound without touching the soundcard usb plug when it becomes unstable with only u-mix44 plugged-in.
I tryed multiple usb ports, rebooting the laptop, reinstall both asio and mixvibes driver, and made sure of no usb power managing.
I'm thinking of some compatibility issues with my built-in sound card wich is 5.1 emulated (IDT HD Audio).
From Asio control panel the u-mix44 is not listed as a device, and from window's devices control panel u-mix44 use a microsoft driver but I find no way to make windows use the mixvibes driver.
Hope I gave enough details and one of you will be able to help me fix this.
Thank you ^^