Question : opening port 20 and 21

I'm at a friend's house and am unable to get my FTP to work. I think that this is because ports 20 and 21 are being blocked. My FTP (WS_FTP Pro) says specifically that these ports are used by the service. I used the online service yougetsignal.com and it says that both ports 20 and 21 are closed. I called my ISP (Comcast) and they said that they do not block these ports, I disabled my windows firewall and AVGfree antivirus. Is it possible that my router is blocking these ports? I've done stuff like this before but am far from experienced at it. Any advice as to where I go from here would be appreciated. Thanks.

Answer : opening port 20 and 21

If you are connected to the internet through a linksys or similar router, that will block ports 20 and 21 from accessing the network. Could you elaborate on what type of router you have (Like what brand)?