Please be advised that this is a known Microsoft bug involving an outdated Microsoft Proxy Server that your Internet service provider (ISP) or local area network (LAN) may be using. The suggested solution is to notify your proxy administrator of the issue and have it follow the steps in Microsoft's relevant Knowledge Base article. Please provide this article for reference when reporting the issue.

You can also search the Microsoft Knowledge Base for any other specific issues that you may encounter with FrontPage.