Okay, so after further researching, I discovered that you really do need an audio output device to get this to work. Plugged in some headphones, and it captures like a charm... kind of a weird glitch I guess, but I'm just glad it's working now.
Just had this problem in CS6 too.
Crashing and error message when trying to capture, until I turned my audio inteface back on again.
Thanks for the fix!
I'm running Premiere pro cc on a Lenovo Thinkpad, and I've got the same problem. So plugged in some headphones, and nothing happened. Is there another solution for laptops?