problems sharing big files

hi friends i have a problem sharing big files, for exmaple when i want to share big files about 700mb i just cannot, but when i press the direct conection buttom and there i have to put the IP of my friend and when i put his IP there displays an error message, i think that it must be for the firewall i dont know how to deactivate it. one more thing in the field where i have tu put the IP there are some letters that said " you are under a firewall connection and yuo wont be able to connect" well the message is something like that, ok friends if someone can help please write me ok

What your speed? Cable? DSL? Dailup?

If you are a dailup, just switch to Leaf mode

ok man i have dsl connection and please tell me which ones are the steps to share big files ok i need it asap thank you som much for everything byeee best regardss