Norton Security Suite blocking RPC connection to SBS 08

As the title says, I cannot seem to get client computers to accept a specific connection from SBS 08.

 

I've turned off Windows Firewall just to be sure it's not a conflict.

 

When I turn off the "smart firewall" feature on the Security Suite, it fixes the problem immediately.

 

I've done the obvious and added a rule that takes connections on all ports from the IP and Subnet of the SBS. This does not solve it, and I just can't seem to come up with any more ideas. Typically, when I add a rule, it listens.

 

Thanks for any suggestions.