This error may occur when the client PC tries to resolve a URL for the
Update site and is unable to find the correct IP address.
Resolutions
1. Clear your local proxy cache on the machine.
Click on Start, and then click Run.
Type cmd in the Open box to get a DOS prompt.
Type proxycfg -d at the command prompt, and press Enter.
Type proxycfg -u at the command prompt, and press Enter.
Now try the site again.
This should work right away, with no other restarts needed.
2. Try using different DNS servers. It's possible that the ISP's DNS
servers are having problems; although if this is the case, it should
only be temporary as the ISP should be working to correct any issues.
Contact ISP or network administrator for more information regarding DNS
configuration.
3. A misconfigured Proxy/Firewall can cause this problem. Double-check
the Proxy/Firewall settings. For help configuring Proxy/Firewall refer
to documentation or contact the manufacturer.
4. Check your HOSTS file and make sure you do not have any static IP
entries for the Windows Update web site listed in the file
Depending on the operating system the HOSTS file can be found in:
Windows NT/2000 - C:\Winnt\system32\drivers\etc
Windows XP - C:\Windows\system32\drivers\etc
To view the HOSTS file, you may need to associate the HOSTS file with
Notepad. To do so, right-click the file, select open or open with, and
select Notepad from the list of programs. If the HOSTS file contains a
static IP address associated with Windows Update, comment the entry by
adding the # sign at the beginning of the entry or delete the entire
line and save changes to the HOSTS file.
Applications like web accelerators, Tweak Master DNS, Spyblockers, etc.,
can add static IP entries for the Windows Update site into your HOSTS
file, which cause Windows Update to fail. "
