1) Can you launch a browser and browse the Internet on that machine? If the machine is in "offline" mode this may happen. Launching a browser may correct.
2) Perhaps the software firewall is blocking this application for accessing the Internet? Usually this is under and Advanced setting called Program Controls or something to that effect.
Advice I have found on this error on other pages:
2) The second one is a longer shot because you force a reload. The browser cache may be damaged with the index no longer matching the content. Explaining a "file not found" result. This would not be uncommon when the user runs some kind of crummy cleaner tool. Just deleting the files from the cache directories is easy but updating the index is not since it is almost always locked. Easy to test if this theory is correct, just ask the user to empty the cache through Control Panel's Internet Options applet.
3) Given this info, I would guess these users have a firewall (or some type of security software) that has hooked wininet and is interfering with your call. Alternatively, they may have malware infestation.
4) One other WUWU user reported this issue. They wrote: "I installed spybot search and destroy amd ran the immunization tool. Now everything works just fine. I'm not exactly clear what this all means. Pete" http://tech.dir.groups.yahoo.com/group/wuhu_software_group/message/15041