Shared internet can't get past antivirus

I have several computers on dial up access (only thing available for temp. situation). I have the computers networked and have utilized the windows internet sharing option so I can access from all computers. I am running Windows 98 on a 650 mh with 256 ram.

When I installed Panda Titanium 2005 for antivirus, the software disables the internet sharing option and starts conflicting with outlook and/or outlook express.

I can run the antivirus on one computer without the sharing option and get access to the net and email but as soon as I install the internet sharing option, the software locks out all access to the internet for other computers and starts a conflict within the main pc.

Any ideas on how to get around this?
Thanks in advance for the help.
jbicon