Outlook Win 98 and XP dial up conflict

Hi,

My Grandparents are still running a 56k dial up connection. I am installing a new computer for them on XP PRO and office PRO 2003. The problem is with an outlook account

pop.freeserve.com
smtp.freeserve.com

this works fine on the computer with my home wireless sending and reciving. However when I use the same computer with her exsisting dial up connection I can only recive????

The strange thing is her existing win98 PC works fine on the current connection.

I have tried telenet on the dial up with no responce, but obviously I get a positive responce via my wireless.

I would like to resolve this so the old guys can access their email and send over their existing connection, any help greatly appreciated!