Hi Gopi
My guess is you are using WarFTP to setup an FTP server on a Windows computer.
Have you tried accessing the server via an FTP client like Filezilla. Try doing that and try navigating around to see how the directory structure looks like. This might give you an idea of how PI as a client would behave when logging into the server and traversing the directory structure.
If you have issues reading/writing file from PI. Try first to manually upload/download/rename/delete using Filezilla to see if it is related to permissions issue.
Regards
Eng Swee