When a user tries to add a Web folder to My Network Places, they receive:

The folder you entered does not appear to be valid.

This behavior occurs if you implement a policy that redirects the user's Application Data folder, or you modify the registry to redirect the user's Application Data folder.

These actions prevent the Add Network Place Wizard from creating a Msdaipp sub-folder, which is normally created under %userProfile%\Application Data (normally "C:\Documents and Settings\\Application Data"), because it does NOT know how to deal with the redirected Universal Naming Convention (UNC) path, if you redirected the Application Data folder to a network server.