Importing To Outlook from Outlook Express Problem

I have been using Outlook Express and there are a lot of folders and emails
in my Outlook Express.

I tried Import the Outlook Express into my Outlook and not all of the
e-mails were copied over. There are many folder names that are empty. It
looks like there isn't enought space in Outlook to store my Outlook Express?

Can someone help me in suggestions to move my Outlook Express folders and
address over into Outlook.

I am using Outlook Express 6.0 and my Outlook is 2003 Sp3

Thank You,

G