Help With FTP service in XP Pro

Specs: XP Pro Corp. Machine, SP2 w/ all updates, Netgear M814 Router, firmware version 4.09, static IP from suscom, port foward on 21, windows firewal set to allow port 21 TCP:

heres the problem, I am trying to set up a ftp server using the basic IIS services with XP Pro. i checked port 21 using the tools found at www.no-ip.com and it said that port 21 was visible when i try to access the ftp server by typing in the ip in a browser window (ftp://x.x.x.x:21) it wont let me see the ftp server. however if i use ftp://192.168.0.6/ from any computer behind the router it works fine. i have tried to figure this prolem out for some time but cant quite get it. any help would be great
thanks, doug