MS has a policy that they don't support upgrades from betas to full release products. Now I know that you're not upgrading from a beta, but I wonder if it falls into the same category.

I'd uninstall the eval version and then reinstall the full release. Do a full database backup before uninstalling, remove the eval version, install the full release, and then restore the backup. SQL Server will recreate the database files from information stored in the backup.

You could test this by first installing the release on another computer and then restoring the backup. I'm confident that it should work.

-Mike