Here are the requested option definitions. See also,
man ftp
-i Turns off interactive prompting during multiple file transfers.
-n Restrains ftp from attempting ``auto-login'' upon initial connection. If auto-login is enabled, ftp will check the .netrc (seenetrc(5)) file in the user's home directory for an entry describing an account on the remote machine. If no entry exists, ftp will prompt for the remote machine login name (default is the user identity on the local machine), and, if necessary, prompt for a password and an account with which to login.
-v Verbose option forces ftp to show all responses from the remote server, as well as report on data transfer statistics.
ksh -x <script name>
This is a debug mode of sorts, that displays all commands and arguments as the script executes. Remove the line as its not needed. Use a log file instead.