Help me redirecting dynamic IP

Hello, I recently visited a free hosting NO-IP.com many as you shall know that you redirect your domain to your private IP across a small program you installed.
The fact is that from my browser, both the desktop and laptop PC that I have networked, I can access the FTP server through the hosting but I tried it in the library and a cyber and nothing at all.
Happy holidays.

Intel Dual Core 3.4 --
ASUS P5N32deLuxe. 1 ethernet nvidia + 1 ethernet PCI 16x
router comtrend HG536+
2 Gb ram 667Mhz; nvidia X500 512 MB DDR3;
win vista HOME PREMIUM; NOD32 total security 3.0.650.0
Firefox 3.0.1
connection 3808/864 Kbps.
home network:

Surely you missing open port to use FTP to the private IP and server where you have installed.

Because if you open the port on the router to the corresponding private IP, since Internet traffic does not reach its destination.

Sorry, I forgot to mention, that if I am not mistaken, that is normally used but he who assigned me. I suppose the fact that libraries and cyber use some proxy will have nothing to do, right?.

Unless the FTP server have the option to allow connect via HTTP, you must connect with an FTP client, the problem may be there.

Check that you have correctly open ports to the IP server.

Besides, if you try to connect to a port other than the usual, you must connect through that port, that is, your address non-ip: Previously used.