I don't think FP 2000 gets this error (but I could be wrong) so I'm assuming you're using FP 98.
By default installation the Personal Web Server should be in your tray (near the time) when you start your computer. This has to be on for FP to work right. If you do not have an icon for it in your tray when you start windows, do a search (Start, Find, Files & Folders) for Inetsw95.exe When you locate it double click on it. That should put the icon in your tray.
Right click on the icon and choose Properties. Click the Startup tab at the top of the window and be sure the line that reads "Run the web server automatically at startup" is checked off.
This should make the web server start every time you start the computer and you should not get this error.
Any time you lose your connection while using FP you will get this error again. To fix it then close the FP Explorer and re-open it.
Good luck,
Bunni Dot Com