Thanks for the quick reply.
Interesting. We are on V7 of UBB and when I click Group Management, there are 2 tabs, Group Editor and Group Access. I don't see a Site Permissions option.
Also, the group "Guests" is not in the list of groups in the Group Editor tab but it is in the Group Access tab. If I click the Group Access tab, I have set Access Permissions to No Access for the Guests.
Can you point out what I'm missing?