[CentOS] squid timeout error

Dear All,

        i am using squid-2.5STABLE 

Below error message occurs if the site is accessed through proxy server.

same problem occurs for many other sites likes dkc1.digikey.com

But the same site opens clearly without any problem if accessed directly.

Please help 

Thanks in advance.
 
ERROR
The requested URL could not be retrieved

While trying to retrieve the URL: http://www.wisegeek.com/

The following error was encountered:

    * Connection to 174.132.22.20 Failed 

The system returned:

    (110) Connection timed out

The remote host or network may be down. Please try the request again.

Your cache administrator is root.
Generated Sat, 31 Jan 2009 13:15:14 GMT by proxyserver (squid/2.5.STABLE14) 

when checked in access.log

TCP/MISS 504 www.wisegeek.com 
error messages in the squid logs file

Regards,
Gopinath M.