Unable to resolve hostname?

[SandMasta]

I keep getting the Unable to resolve hostname error with every server I use, all the info I enter is correct. Before I even press connect I get this error and once I do it gives me the same error. Any ideas would could be causing this? I highly doubt it is my router, have a D-Link gaming router, windows firewall disabled and norton is out of subscription. Using windows Vista

[Prog-Rocker]

[COLOR=black][FONT=Verdana]This error is caused by the Domain Name System (DNS) cache being out of date. DNS is a TCP/IP function that converts a Hostname to an Ipaddress. The cache can either be local or on an upstream DNS server (depending on how your TCP/IP settings are configured).[/FONT][/COLOR]
[COLOR=black][FONT=Verdana] [/FONT][/COLOR]
[COLOR=black][FONT=Verdana]To clear the local cache power off the modem-router-pc (in that order) for at least 60 seconds. If you still get the error message then the problem is further upstream. The following instructions are a temporary work-around:[/FONT][/COLOR]
[COLOR=black][FONT=Verdana] [/FONT][/COLOR]
[COLOR=black][FONT=Verdana]This site will allow you to lookup the ipaddress based on a hostname.
Type in the following into a web browser:

[url]http://network-tools.com/[/url]

Enter the full server hostname (from the server setup in ventrilo client) in the box, select “Network Lookup” then click the "Submit" button. The ipaddress you need will be listed on the left-hand side of the screen.

In Ventrilo --> Server, enter the ipaddress in place of the hostname.

Note: before changing the server info in Ventrilo, write down the hostname so that it can re-entered after the DNS issues have been resolved.[/FONT][/COLOR]