Internationalization of the File Transfer Protocol:
http://war.jgaa.com/ftp/rfc/rfc2640.txt
FlashFXP displays ???? because Windows uses Unicode(UTF-16, maybe UTF8?) for file/directory names and since FlashFXP uses ANSI strings internally, a conversion has to be made. Because my locality is set to Finnish, the program attempts to convert these names to latin-1 (as opposed to shift-JIS which would be appropriate for Japanese characters) and because these characters do not belong to the latin-1 character set the converted string is instead filled with question marks.