Squid configuration

I have installed squid 2.4 Stable 7 on Linux 7.2. After configuring squid.conf, I am getting the error as “Forwarding denied”. I want to know what is to be configured for the same. Some times I get error as “Access Denied”. I can browse FTP sites through Squid on local machine(Machine which has been configured as proxy server) but I could not be able to access it through clints.