NPE 1.7 remote scan doesn't work

Hi everyone,
On my win 7 pc 32bit with NIS 2011 18.5 installed I run NPE 1.7.0.3 Italian and when it find some suspicious file it gave me the possibility to remote scan them. I click “remote scan” but after few seconds appear “operation failed”. It seems that NPE doesn’t comunicate with remote scan servers.

How to solve?

Thanks in advance for repies.