I am sharing certain specific files using limewire, yet when a friend searches for these files using limewire on his computer, they can't be found. Does anyone have the answer???

That problem occurs because you cant connect
to all nodes in the Gnutella Network and so you have a limited horizon for your searches.

You can solve this problem by connecting directly to your
friend using the Connection Tab.
Simply enter your friends IP and his port (I guess 6346).

Then it should work.

Actually, that doesn't work worth squat unless the person you are trying to hit is acting as an ultrapeer.... That has been my experience anyway. On the other hand, if both users are using lw that supports host browsing, you can type the host ip address in the search field and browse the host ... that does work for me.