Webshield blocking all internet traffic.

When I turn on the webshield, I am unable to connect to any internet sites. I receive “connection reset” or “no data received” error messages.

If I run the network diagnostic, no error is found and all lights are green.

When the webshield is turned off, the problem is fixed and connectivity is restored.

Ideas?

Are there any relevant messages in the system log (var/log/system.log)?