Until about 18 months ago, LW Pro support & updates was only for a 6 month period. After which they offered a discount to continue for a limited time. Now they offer a 12 month extended version as well. In your case, over 3 years ago your Pro support will have finished February 6, 2006.

If you wish to upgrade to LW 5, you can get LW Basic or purchase Pro. Your choice. I'd suggest you wait, try LW 5 Basic out & see if you like it or not. LW 5 should not have been released so quickly, it was not ready. But they still offer LW 4.18 to download & install. A high % of people are downgrading to LW 4 after trying LW 5.