If your JMP program runs in Windows, you can create the FTP script and run it using JSL.
Below the JSL example copies all files having names starting with FILE_NAME in the FTP directory using mget command.
ftp_txt="
\!nopen 192.168.1.10
\!nuser FTP_USER_ID PASSWORD
\!nftp
\!ncd FOLDER/LOCATION/
\!nlcd C:\LOCAL\FOLDER
\!nprompt
\!nmget FILE_NAME*
\!nbye
\!n
";
save text file("c:\test.ftp",ftp_txt);
cmd_txt = "ftp -v -n -s:c:\test.ftp";
save text file("c:\jmp_ftp.bat",cmd_txt);
wait(1);
open("c:\jmp_ftp.bat");