N360 and NIS - different virus definitions?

Hello everybody,

 

Please explain me this strange situation: I have 2 PC - one with NIS 2010 and another with N360 v4. Yesterday I downloaded the virus http://www.virustotal.com/file-scan/report.html?id=41e19d03853208caec30a3c6c9bffa038e6b03f0a021b24bbac092dbdbff788c-1282064632

And now is funny story: my NIS detected this virus but my N360 (fully updated) can't.

I even made fresh windows and N360 installation on a virtual machine - the same result. So, I can run the virus and no warning messages from N360, only when I tried manually start Insight Network Scan I got message about WS.Viral.1

 

Does it mean N360 and NIS use different virus definitions? Or what?