What OS are you dual booting? Is it Linux and Windows or something? As Smash says, 98/SE dont support all newer Ethernet connections, there is a program to patch this though.
It appears that this person is dual booting two XP! Why would you want to do that. What is your reasoning. I understand if you are dual booting two different operating systems but why one that is a waste of space in my book.
Anyhow, you have to install the router for each partions as it treats it like two seperate hard drives.
You need to make sure your router is configured correctly depending on the computers settings.Each computer is assigned a different IP you need to make sure your router is configured correctly for them both.Good Luck.