Norton 360 blocking network connection?

I got a new laptop and installed N360 (from Comcast) - as I had done with several other computers in my home office.

I cannot access any other computers in my network, even though it sees all of them. Error message says something like "network path not found...remote computer is online but not responding to connections attemps on port 445, possibly due to firewall or security settings..." 

The other computers on my network (running W7, Vista and even XP) can see this new laptop on the wireless network but cannot connect either. They do connect to one another fine.

Can anyone help please?     

A T