Passive FTP Mode
This has nothing to do with HostGator, and everything to do with your FTP program.
Go into your FTP options and see if passive mode is checked ,if it is, uncheck it. If it is not checked, try checking it.
If you are behind a router, you will normally enable passive FTP mode.
If you do not know how to check this setting, you need to consult the help documents of your FTP program.