When I installed Mixvibes a couple of months back I had the same problem.
I think you should Uninstalled the software and driver, and then:
1> Install mixvibes
2> download Update of mixvibes (7.1)
3> download u46MK2 driver update (1.041)
4> Install Update of mixvibes
5> Install driver
6> Restart computer (with Mixvibes hardware off!!)
wait 10 seconds
7> Turn Mixvibes hardware ON
wait 10 seconds
8> Launch the Mixvibes software
This helped me out
