Hi BIGHEADover50, in simple terms:
Software like IE 6.0 does not seem to know how to cope well if there is a Firewall box in the mix and ports are other than 21.
Actually the Firewall boxes have specific code in them to allow FTP to function through the box like port 80 can. The code is designed around port 21 and does not take effect if the port number is something else.
A few FTP Client programs (Newer versions) seem to know what to do in this case. One that seems to do the trick is FlashFXP, even if you use various port numbers.
