What is ARX MIDI Ports?

I put Sonar X1d on a new 64 bit Win 7 OS, and when I ran Sonar, I got the message:
 
Cannot open ARX MIDI Ports. Ensure ARX is connected and that MIDI ports are not
selected in the host.
 
Thing is, I have absolutely no idea whatsoever what ARX is. When I changed OS, I didn't
change any hardware, so this is a new message for me.
 
Any thoughts, or ideas?
 
(Sonar runs, so I can move forward. I just don't know if I have a problem or not, hiding somewhere.
Maybe Sonar wants me to write a song called "ARX - who are you?"

Interesting. I don't have ARX checked off under the MIDI port assigments. There is one thing though, when I was installing Sonar, there was one file that didn't get written to the temp folder on the first try, and I had to click "retry" to continue. The file in question was
something like "vscredit", I didn't write down the file extension.
Since that file starts with "VS" I wonder if that's my problem.

Thanks for the tip, and I'll snoop around some more. At least the message is a logical one to get, and its not a fatal error!