1) This issue may be caused (repeatedly prompted for a user name and password) by not having the Client for Microsoft Networks installed in your network configuration. To find out if it's installed, go to Start - Settings - Click Control Panel - double click Network. Look in here for the Client for Microsoft Networks, it should be the first item listed. If not, then it should be added by clicking the add button then double click "Clients." In the Cfg window click Microsoft then in the Right hand window, click on Client for Microsoft Networks. Then click OK some files will be copied and you'll be prompted to restart.
2) This could also be caused by the domain name not being propagated to our network. It may still be pointing to the previous network and the username and password would not be valid for the previous host. If experiencing problems described, always check the WHOIS to verify that your domain points to our DNS servers first.
3) You could be behind a Proxy or Firewall that will not allow you to connect correctly. Contact your network administrator for help.
4) On Internet Explorer click on tools, internet options, connections, LAN settings, and make sure that nothing is clicked...no proxy server. In FrontPage, you can get to this setting also by tools, options, under the general tab, click proxy settings, under connection click LAN settings and make sure that nothing is highlighted. Other tech support information is available at Microsoft FrontPage Support
5) Upgrade Internet Explorer to the latest version of 5.6 or 6.0