Seems like the extension creates a 2012 version of the dbf file, you can not attach that to 2008.

I would download the deployment center and create the clean database with that directly against your 2008 database server.

You might run this sql query before attaching to SQL Server 2008:

ALTER DATABASE VJ_DATABASE
SET COMPATIBILITY_LEVEL = 100;   
GO

Or this:
http://stackoverflow.com/questions/26346647/the-database-cannot-be-opened-because-it-is-version-782-this-server-supports-ve
Regards.
/Q

I stumbled on then when opening an existing project in Visual Studio 2015 with a local database in App_Data.

The solution was to change the connection string, from;

Data Source=(LocalDb)\v11.0

to

Data Source=(LocalDB)\MSSQLLocalDB

Hope this helps someone
Fredrik

You need to downgrade the database.

If you dont have any sql management studio for the newer version, install an express version to do the down grade in

Right click on database
-task
-generate script
-choose entire database
next setp
-advanced button
-script for specific version(choose wich version u want)
-type of data to script(schema and data)
-choose location
next step
...

When you have the script run them in the sql 2008
Its important that you change the location of the databasefiles in the script before runninge them