Hi Dave, I'd be interested in hearing about what FDG might have to say. Iirc, you as well as Eric P and other Dakota users were at one time even offering to pay for them to develop new drivers, and they did eventually release some (beta?) drivers for Win7.
Also, as you had indicated that your Dakota was working fine in X1, I'm kinda curious about what may have changed between X1 and X2 wrt how Sonar interacts with the Dakota's (or other interface's) drivers.
Oh, and for everyone recommending RME, yeah right. Try using a 'Hammerfall 9652' or 'Digi 9652' in x64 Windows. And be sure to check RME's forum for how they respond to people trying unsuccessfully to do just that - "it's an old card, what do you expect, it still works in 32-bit Win7 and x86 Linux so don't complain. You have to buy the HDSP card for x64."