Data at the root level is invalid. Line 1, position 1 in MOSS,WSS

Today when I working on wss 3.0 / MOSS site suddenly I got an error saying , "Data at the root level is invalid. Line 1, position " . Then I come to know I have open one html file from virtual directory in SharePoint Designer, SharePoint designer automatically geneates some folder inside this directory which is the cause of an above error. so when I deleted this folder named "_vti_cnf" then site works fine..

Virtual PC for sharepoint

To install and use windows server 2003 and sharepoint features. Virtual PC is the best tool to make a test run and make development on your windows xp or vista operating system, and it is lot better then having dual OS on the machine.
Below is the link to virtual PC
http://www.microsoft.com/windows/products/winfamily/virtualpc/default.mspx

From below link you can download virtual hard drive which has 30 day trial of window server 2003,
http://www.microsoft.com/downloads/details.aspx?familyid=77f24c9d-b4b8-4f73-99e3-c66f80e415b6&displaylang=en

First step towards sharepoint

It is my first step and first blog towards sharepoint,
below are the most popular available links and blogs for sharepoint,

http://www.microsoft.com/Sharepoint/default.mspx
http://www.sharepointblogs.com/
http://blogs.msdn.com/sharepoint/
http://sharepointsolutions.blogspot.com/
http://office.microsoft.com/en-us/sharepointserver/default.aspx