Upgrade to WP2 Moving Hosts

My website was down for a few months and I’ve finally gotten around to resurrecting the domain, just in time for the release of WP 2.0. The problem that I’m having is that all my backup files are for WP 1.5. If I try and upload those older files to the WP2.0 database as per the ‘moving’ instructions, it causes errors. Generally all the posts are there, but the categories are absent and I lose all ability to post or edit new posts.

Is there some way I can import the posts from these older backups into my new WP2.0-based database?