Warning: Unable to open MIDI ports to the VS-700R. Make sure that the VS-700R is connected and its MIDI ports are not in use by any other application
 
 
In the V-Studio Access Panel MIC PRE & DIRECT MIX are greyed out so that section isn't accessible either.
Hoping it's something I have checked or not somewhere.
All drivers as far as I know have been installed properly. I'm able to control Sonar from the 700C
 
 

All good, solved on my own. It was in the control surfaces section I needed to add and ACT midi controller with MIDI as the ports.

Dahjah..I'm just after posting the same problem. What did you do to solve it ????? 

Yeah IO 700 can't be checked in midi devices but IO MIDI should be checked.
ARX also can't be checked.