Messenger Help!!!

Hi. I have been facing some problems with my messenger and
I don't know what is going on.

I Live in UK and I am communicating to a guy who lives in Brazil I have Dial - up and He's got a Cable connection and every time we connect his messenger is dropped .(logged off) I just have to send him a message and he will be logged off. I know that there are many servers in Brazil that will block International IP but I don't think this is the problem. because he will be logged off only when I start typing
Thanks

Which Messenger versions and OS versions are you both using? Do either of you have a firewall?