Hi maddog,
I don't have any experience with the DAC-2, but I'm sure somebody around here does. I just noticed that you've been around since '04, so you'll have to re-input your serial number into your profile and grab the latest update (7.3). The only other thing I can thing of would be to grab the latest DAC-2 drivers here:
http://www.pcdj.com/index.php/support/drivers.
*On a side note, make sure you have your controller plugged in before you start MV and that you've activated it within the software.
Hope this helps,
Phaded