550 failed to change directory (Internet explorer only... particular server only)

I have a problem, which I hope is an easy fix.

I can access an apache ftp server (with remote directories) with 3rd party ftp software, but have issues when I use IE.

I believe the problem to be on the server end, because I can use IE to access other ftp servers, targeting subdirectories off of my root.

I can however, log into the apache ftp server via IE, if I only use the root address. It is when I try to add the /var/html/www...... after the ip address, that I get "550 failed to change directory".

This problem is specific to a particular server. As I said, I can use IE fine on other servers.

I am not real familar with LINUX or Apache, but will make sure all your responses get to my collegue, who is more familar than myself.