consegui resolver o problema do Squid referente a esta mensagem
ERROR
The requested URL could not be retrieved
While trying to process the request:
GET / HTTP/1.1
Host: tecmundo.com.br
Connection: keep-alive
Accept: text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,/;q=0.8
User-Agent: Mozilla/5.0 (Windows NT 6.3; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/40.0.2214.93 Safari/537.36
Accept-Encoding: gzip, deflate, sdch
Accept-Language: pt-BR,pt;q=0.8,en-US;q=0.6,en;q=0.4
Cookie: __utmt=1; __gads=ID=937e8b406cf84246:T=1422369482:S=ALNI_MY8R2DxHOsYGla4XRbONnaT_g2T9w; __utma=45109281.1907218561.1422365895.1422365895.1422365895.1; __utmb=45109281.3.9.1422365905416; __utmc=45109281; __utmz=45109281.1422365895.1.1.utmcsr=(direct)|utmccn=(direct)|utmcmd=(none)
The following error was encountered:
Invalid Request
Some aspect of the HTTP Request is invalid. Possible problems:
Missing or unknown request method
Missing URL
Missing HTTP Identifier (HTTP/1.0)
Request is too large
Content-Length missing for POST or PUT requests
Illegal character in hostname; underscores are not allowed
Your cache administrator is webmaster.
e tambem consegui resolver o problema do squidGuard nao iniciar, depois de muita dor de cabeça descobri que precisava limpar o cache do squid através do comando
rm -r /var/squid/cache/*
e incializar novamente pela interface ou pelo comando
squid -z
este e o link onde achei a soluçao.
http://cpdsolucoes.com.br/site/blog/?p=110
obrigado a todos.