The previous installation of Windows SharePoint Services v3 on this server contains one or more content databases that are ...

The previous installation of Windows SharePoint Services v3 on this server contains one or more content databases that are too large to be attached to SQL Server Express 2008.
If the required support files are installed, before upgrade occurs a process will be initiated to migrate the existing databases to the SQL Remote Blob Storage FileStream Provider when moving a copy of the databases to SQL Server Express 2008.
If the migration fails, the original databases will be preserved in their existing unmodified state. The migration will extend the amount of time that this installation takes and will require additional space on the hard disk.
Please refer to the following location ("http://go.microsoft.com/fwlink/?LinkId=159867") for more information about this migration process and to download the required support files which must be installed before continuing.