Not possible to copy files from FTP server using Filezilla. The error in Filezilla:
Error: Failed to open "D:\comments.php" for writing Error: File transfer failed
You are not allowed to write to the mentioned drive/directory in the error message.
Please select a directory in Filezilla where you have Write access (inside your user profile for example) and try to copy file from FTP to this directory once agian.