NIS 5 for Mac Idle-Scan does never run on OSX 10.7.5 (Lion)

Hello,

 

I bought and installed Norton Internet Security 5 for Mac yesterday. I realized that idle-scan never runs, eventhough my Mac is idle for extended period of time.

 

My Mac:   Intel Core 2 Duo 2.4GHz, 8GB RAM, with Mac OS X 10.7.5 (Lion) 

 

How can I fix this problem ? Anybody can help me ?

 

Thanks,

Tolga