I have installed VS-20 on W7 64bit twice and continue to get this message when I open the Editor.
Also, I try regardless to define Midi I/O devices but, when I Apply/OK the dialog, it insists that I haven't defined any.
I have tried USB sockets at the back and on the front of my PC.
I have a Saffire Pro 40 connected vi FireWire already - is this the problem?
Has anyone any experience or ideas how to get the VS-20 working so that I can get my hands on the great guitar effects to use with my X3e Producer DAW.
Thanks to all in advance

If you are using ASIO drivers for both it will not work as ASIO only permits one device at anyone time.
 
Are you defining the ACT device for your VS 20?

Thanks Wookiee.
I suspected that it was the multiple ASIO drivers thing.
To access the COSM effects in the VS-20, I have installed its driver and the editor on a laptop and taken the output from the VS-20 into my Saffire interface to my main PC where Sonar is.
This way, the signal goes from my guitar through the VS-20 on the laptop and out into Sonar on the PC.
I can also use this setup, with/without COSM, through the VS-20 line-in, for the output from my GR-30 guitar synth.
The connections remain alongside each other on the VS-20 so all I have to do is push a button to switch between the guitar and line inputs on the VS-20 without having to swap or use additional inputs at the Saffire end.
A roundabout configuration but seriously effective.
Of course, this means I cannot use the VS-20 as a DAW controller for Sonar on my PC but that does not bother me.

Glad you got it working.
 
One thing you could try is to install the VS20 on your main DAW then disable the AUDIO within SONAR under preference, make sure that all other parts refer to the saffire for audio timing etc, this may then allow you to have the best of both worlds.  You would still need to feed the Audio output from your VS20 into your saffire.