Error on SQL Server 2000 backup (.bak file) restored on SQL Server 2012
The database is a SQL Server 2000 database (version 8.00.2055) - and you cannot directly update a SQL Server 2000 database to SQL Server 2012.

You'll need to take an interim step first (restore it in SQL Server 2008, back it up from that server again).

See the relevant MSDN documentation:


  In SQL Server 2012, you can restore a user database from a database backup that was created by using SQL Server 2005 or a later version.


but SQL Server 2000 is NOT supported.