Transfering emails from one computer to another.

I purchased a new Macbook Pro and I need to transfer all my emails from my old Powerbook, to the new Macbook Pro. I'm using Entourage 2004. I tried copying the Microsoft User Data folder from the powerbook and replacing the same folder on the new laptop. IT works, but it's not copying the past months worth of emails. Basically, it's only transferring from Feb 2007 to ealier, not none of the current emails. Is there a reason form this?