Try switching off your software firewalls and see what you've got.
This same problem started on my machines a couple of days ago. I really haven't figured out what's going on but I think the superhub is involved somehow.
Although I have assigned static IP's to both computers and the NAS, the firewall logs show blocked pings from 192.168.0.2 to 192.168.0.255, of course 192.168.0.255 should be 192.168.0.3. Strangely the NAS on 192.168.0.4 is not affected. Other wierdity is firewall auto-detects the network on 192.168.0.0 using the Superhub. Using other routers it is detected with the same IP as the gateway. Seems the Hub might have it's knickers in a twist.
In the meantime I have had to manually 'Allow' all system services on the firewalls on both machines to get my network up and running.
I think a pin-hole reset and then set-up everything again from scratch may be the only way to sort this mess out.
I'm getting really fed up tinkering with it. I've had nothing but problems of one kind or another since I installed it.
I had an ordinary Hub before and it was quite stable.