Can you try running the following script in Management Studio. The error message doesn't indicate that this is the problem, but it will not do any harm to make sure NBNUser is correctly set.
Mike
IF NOT EXISTS(SELECT * FROM Master.dbo.SysLogins WHERE Name='NBNUser')
CREATE LOGIN NBNUser WITH PASSWORD='NBNPassword', CHECK_POLICY=OFF
EXEC sp_addsrvrolemember 'NBNUser', 'dbCreator'
EXEC sp_addsrvrolemember 'NBNUser', 'diskAdmin'
USE NBNData
IF NOT EXISTS(SELECT * FROM SysUsers WHERE Name='NBNUser')
CREATE USER [NBNUser] FOR LOGIN [NBNUser] WITH DEFAULT_SCHEMA=[NBNUser]
GO
EXEC sp_addrolemember 'db_backupoperator', 'NBNUser'
EXEC sp_addrolemember 'db_datareader', 'NBNUser'
EXEC sp_addrolemember 'db_datawriter', 'NBNUser'
EXEC sp_addrolemember 'db_ddladmin', 'NBNUser'
EXEC sp_addrolemember 'db_owner', 'NBNUser'
EXEC sp_change_users_login 'Update_One', 'NBNUser', 'NBNUser
Mike Weideli