Rename does not work, why?

I'm using WinSCP 2.2.3
The server is OpenSSH on Windows v3.4-3
After I log in successfully, I try to rename a file or directory, I get this error message:

Command "mv -f "FileA" "FileB""
failed with return code 127 and error message
mv: not found.

I have permission to create and delete files.
What's wrong?

Thanks.

OpenSSH server for Windows does not have MV command, so renaming cannot work. You can wait until WinSCP support SFTP protocol.