Denied Connection by unknown rule

Hi, I created a rule to allow certain internal workstations to connect to a file share of the ISA 2006 SP1 server.  But the Netbios session (along with others RPC ports like 135, 137, 445...) connectin was denied.  Checking the log, I see this:

Denied conenction
Log type: Firewall service
status: 
Rule: -
Source: internal (192.168.176.60:50407)
Destination: Local Host (172.17.10.150:139)
Protocol: NetBios Session
User: - 
Number of byes sent and received are both 0

As a troubleshooting step, I created an access rule with order=1 to allow All Outbound Traffic from 192.168.176.60 to Local Host for all users.  But the connection is still denied with rule = "-".

Can somebody explain to me what went wrong? 

thanks