strange network problems

i have 2 computers. One has 98se and the other XP profesional. if i try to copy from 98se (p3 650MHz 128ram) to xp (>p4 2400+ 512ram) it works perfect. The other way aroud it doesn't (max 0.97% of 10mbs). I wrote you brakets for wat i considered that is necesarly to know.

DId you enable file sharing on the 98 machine?