Error from outside my home net

i, i have my book live connected by ethernet at my AIRPORT EXTREME.

The Device Works perfectly when i am inside my home net, but when i try to open the device by ftp from the internet, i see all the folder and the files, but i can upload or download any files from my MBL…

can anyone help me? 

Thank u !!!

Too many factors may interfere with this.  Since it works in your local network, a firewall in the router were you have the MBL attached, or from the router or computer that you are trying to access it from, may be interfering with the access.