This setup is NOT as straight forward as it seems. You have 3 devices which all have built-in sound cards, and....all send MIDI signals. I think we need to start at the beginning here.
1) Are you using the mixer or cd players as you sound card/s?
2) Are you using internal or external mixing mode?
3) Are you using timecode or just MIDI controlling?
4) List all devices connected to your PC.
You have multiple options with the equipment you have.
A) Use the cd players internal sound cards and run MV in external mixing mode, whereby you run your mixer as a normal stand-alone mixer. This would mean that both cd players usb cables are connected to your PC, but not the mixer.
B) You can use the mixer as your sound card, whereby you run MV in internal mixing mode, the sound will route directly to the mixer (bypassing the cd players) but you will have cd players + mixer's usb cables running to the PC.
C) Run timecode, whereby the timecode signal (hybrid/cd) runs from cd players to mixer, from mixer to PC & sound from PC back to mixer. It's the same setup as above, but you need to configure the input's & outputs.
Also be sure to set the matrix knobs on the mixer channels accordingly - All the way to right (P1,P2,P3,P4) is for timecode. The other (1/2,3/4,5/6,7/8) is for straight forward usb connection. This is also affected by the audio "routing" settings within the mixer itself. I actually owned this exact mixer a while back, fantastic mixer, but VERY involved config. I can't remember all the options anymore - you gonna have to read the manual.
Also - As far as I can remember, the Denon Asio issue is related to "rare" audio drop-outs not connectivity. I would personally recommend using the Denon Asio over Asio4All<-- or use as a last resort. Go to the DenonDj Forum - Silvio or DoubleA will be the guys to properly assist you.
http://www.denondjforums.com/
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