Squid, squid guard

[kalu]

I have squid package installed and running.
i have squid guard installed but it's doing nothing i.e. stopped.
could you guys please help me why such error message comes to some times including pfsense forum
thanks

ERROR
The requested URL could not be retrieved

While trying to retrieve the URL: http://forum.pfsense.org//

The following error was encountered:

Zero Sized Reply

Squid did not receive any data for this request.

Your cache administrator is admin@mydomain.com.
Generated Thu, 18 Aug 2011 11:00:19 GMT by localhost (squid)