Liteserve FTP access problem

Hi, i have this problem

I am running a win2k pro. I just used lite serve to create my ftp server.
After creating it i tried logging in with my normal ftp client from my home network it was working alright but when i tried to log in from over the WAN i get a message saying "windows can't acces the flie or folder make sure you have type the correct file name or folder and you have set permissions to access the file or folder.I have already set full access to the ftp folder but over the internet i get this problem not over the LAN.

I am behind a router i have forwared the default port number and my zone alarm firewall has set to allow ftp access. But i just can't figure out what is wrong can someone help me..

Thank you.

go to www.grc.com and run the shields up test. Check that the correct ports are open to the Internet.

Managed to get it working thanks for the help dude, what was wrong is first i had to set server access to my internet explorer in my firewall second i had to do a port trigger port opening was not enough in this case i don't know why but after doing a port trigger or mapping a custom port to 21 the ftp server could work which is so funny.......Thanks again and if the server crash again i will be back in this thread to get another solution