PMCwebs.com.au is running a heightened security system (firewall) to prevent unauthorised access.  The average PMCwebs.com.au user doesn't need to know the specifics about how the firewall works, except that you are required to set your FTP program to connect in Passive Mode, using ports 30,000 to 35,000.  All FTP programs have this setting and it is usually called PASV.