[Samba] Guarddog, Samba, Win98

[Ovidius]

Using Samba on Kubuntu Breezy, and Win98 on a virtual PC
(VMPlayer). Everything works fine, except:

When the firewall (iptables via GuardDog) is activated, I don't
get any access from Win98 to my Linux shares - neither by
ping nor by "connecting network-drive" - even if I allow everything
that can be allowed within GuardDog (although this should have 
the same effects like deactivating the firewall at all - in my opinion
at least).

Is the solution of my problem to be found in GuardDog or in iptables
or maybe in a certain option in smb.conf? Any hint is welcome.

Greetings
Franz