ME Port Blocking

I have a small problem with Windows ME.
I am using ME on my primary server with ICS to allow access to the internet for my internal network and this works great. My problem is that some FTP sites use ports around 27000 and with ME I find that even with these ports open in ICS I am still being blocked from accessing these ftp servers. Servers with port 21 work fine and i have tried using pasive mode with no joy. 98se didn’t give this problem and I have tried NT (also fine). My firewall is not the problem as i’ve tried with a fresh install and still no joy. Disableing ICS also has no affect. Thanking you in advance for any help.