Unable To Backup Database In UserInstance

I've been struggling with this for a few days now, so I guess it's time to ask for help. I'm working on a VB Express 2005 Single form windows application that uses a SQL Express 2005 two table data base. I can read and write to the database with no problems. I just can't back it up. I haven't tried restores yet. I created the database in SQL Server Management Studio Express and then connected to it from the VB Express application.

My.Settings.UsersConnectionString is

Data Source=.sqlexpress;AttachDbFilename="C:Program FilesMicrosoft SQL ServerMSSQL.1MSSQLDataUsers.mdf";Integrated Security=True;User Instance=True

I used the following code to establish a connection to the server that is the userinstance

Dim SqlConnection As SqlClient.SqlConnection = New SqlClient.SqlConnection(My.Settings.UsersConnectionString)

Dim ServerConnection As ServerConnection = New Microsoft.SqlServer.Management.Common.ServerConnection(SqlConnection)

Dim srv As Server = New Server(ServerConnection)

I am able to confirm the connection to the UserInstance via a message box that displays the instance name

MsgBox(srv.InstanceName.ToString)

Then this code follows:

Dim db As Database

db = srv.Databases("USERS")

Dim bk As New Backup

'Specify the type of backup, the description, the name, and the database to be backed up.

bk.Action = BackupActionType.Database

bk.BackupSetDescription = "Full backup of Users"

bk.BackupSetName = "Users Backup"

bk.Database = "USERS"

'Declare a BackupDeviceItem by supplying the backup device file name in the constructor, and the type of device is a file.

Dim bdi As BackupDeviceItem

bdi = New BackupDeviceItem(AppDir & "Test_Full_Backup1.bak", DeviceType.File)

'Add the device to the Backup object.

bk.Devices.Add(bdi)

bk.Initialize = True

'Set the Incremental property to False to specify that this is a full database backup.

bk.Incremental = False

'Set the expiration date.

Dim backupdate As New Date

backupdate = New Date(2008, 10, 5)

bk.ExpirationDate = backupdate

'Specify that the log must be truncated after the backup is complete.

bk.LogTruncation = BackupTruncateLogType.Truncate

'Run SqlBackup to perform the full database backup on the instance of SQL Server.

bk.SqlBackup(srv)

'Inform the user that the backup has been completed.

MsgBox("Full Backup complete.")

Unfortunately, the line bk.SLQBackup(srv) errors off advising that - Microsoft.SqlServer.Management.Common.ExecutionFailureException {"An exception occurred while executing a Transact-SQL statement or batch."} Microsoft.SqlServer.Management.Common.ExecutionFailureException

and that

+ InnerException {"Could not locate entry in sysdatabases for database 'USERS'. No entry found with that name. Make sure that the name is entered correctly.
BACKUP DATABASE is terminating abnormally."} System.Exception

So I went to SQL Server Management Studio Express and ran the query

use master

select * from sysdatabases

Among other lines the query returned

USERS 5 0x010500000000000515000000358A021AFA4F0C2F828BA628AD8A0200 0 1073807369 1627389952 2007-03-16 10:04:42.320 1900-01-01 00:00:00.000 0 90 C:Program FilesMicrosoft SQL ServerMSSQL.1MSSQLDataUsers.mdf NULL

so it appears to me that the entry for database USERS is really there.

Any ideas as to what I need to do so that I can add a program feature to backup the data are greatly appreciated.

Thank you,

MF