You might want to check on the permissions you have to the Shared Documents
folder. How you do that depends on what version of XP is installed on your
computer. For XP Home Edition, you'll need to boot into Safe mode to get access
to the Security tab. In XP Professional, go to Control Panel -> Folder
Options -> View and disable Simple File Sharing. To restore access you may need
to take ownership of the folder. Take a look a these articles for more info.
"Access is Denied" Error Message When You Try to Open a Folder
http://support.microsoft.com/kb/810881
How to take ownership of a file or folder in Windows XP
http://support.microsoft.com/default.aspx?scid=kb;en-us;308421
Good luck
Nepatsfan