Getting Error : <Error ID="10">FolderNotFound</Error> While using DWS CreateFolder() method.

Question

I am trying to create folder in sharepoint and using DWS.aspx Web Service CreateFolder() method.

Dws ds = new Dws();
ds.Credentials = new NetworkCredential(MyServerId,MyServerPassword,Domain);
ds.Url = "http://MyServerName/" + @"/_vti_bin/dws.asmx";
ds.PreAuthenticate = true;                   
strResult = ds.CreateFolder(FolderPath);

 //Here My FolderPath is "Docs/Documents/Assets/NewFolderName

I am getting strResult value as "FolderNotFound".

I tried solution of below link:

http://social.msdn.microsoft.com/forums/en-US/sharepointdevelopment/thread/a66828f0-c345-4b49-bf64-6ef417d9786b

But still not getting solution.