I'm going to try to explain what happens with mine - probably won't help your situation, but maybe it can...
I have a laptop and when I'm in the office, I plug it into a dock and it connects it to the network. It is then "hardwired" into the server and uses the direct internet (not wifi). When it is setup like that, it behaves like you are describing - it shows some ncraves, but when I click on the I get the sorry message and they disappear.
Some days, like today, I don't need to be plugged into the network. When I don't plug in (and it's using wifi for internet service), the ncraves are there. I'm assuming it has something to do with going through the company's firewall, but I'm really not sure why there is a difference. We are a relatively small company and don't have extensive firewalls installed.
So, most days, I can't run them at work because I need files, etc on the server, but there are occasional days that I can remain unhooked from the network and they run great! Definitely makes me wish that they always ran like this. I've basically done nothing with them and have 74 points! Oh well, at least I can do it occasionally.