new mac-clean rekordbox: how to import what's on usb ?

hey there!

I wanna setup a new database on a new mac and import all the tracks and playlist which are now on my usb stick.

on the old mac I used to have a collection of 300 tracks but always deleted tracks on the usb stick in order to keep an overview. now i don't want to import the cluttered old database, but only the stuff which is on my usb NOW! I don't only want the analyzed files because I wanna build a new database on the mac, so I can work on it while the usb is not plugged in and then export later.

how can i do that?

if I choose a playlist on the usb and try to import it says "list is empty or tracks are not in collection"

is there an easy way to achieve what I want ?

I#m on a new macbook air running Lion.

cheers