Hmm....I'm not really an expert on networking or anything like that, but I have one question and a few other ideas.
1) What kind of connection is it? Wireless/Direct Cable/etc.
2) I don't know if this will help or not, but perhaps make sure that you have file/printer sharing on. I'm guessing you do, but eh, who knows.
3) You don't have a network password or anything, do you? I know there's an option to enter a network/administrative password somewhere.
Again, these are kind of stupid, routine questions, but I personally sometimes overlook them.
EDIT: Wow. I need to type faster or something.