Adding in Data to Database Error

<pre lang="vb">Dim DBConn As New SqlClient.SqlConnection("Data Source=ML0003135586;Integrated Security=SSPI;" & "Initial Catalog=TestSQL")
               Dim DBCmd As New SqlClient.SqlCommand
               Dim DBAdap As New SqlClient.SqlDataAdapter
               Dim DS As New DataSet
               Dim a As Int16
               DBConn.Open()
               Try
                   DBCmd = New SqlClient.SqlCommand("INSERT INTO tblCourses_13514(Course_Code, Course_Title, Objectives, Category, Duration ) VALUES (@Course_Code, @Course_Title, @Objectives, @Category, @Duration)", DBConn)
DBCmd.Parameters.Add("@Course_Code", SqlDbType.NVarChar).Value = drpProCode.Text
DBCmd.Parameters.Add("@Course_Title", SqlDbType.NChar).Value = txtProName.Text
DBCmd.Parameters.Add("@Objectives", SqlDbType.NVarChar).Value = txtProDescription.Text
If drpProCategory.Text = "GEE 51 Bulletin Requirements" Then
                       a = 1
                       DBCmd.Parameters.Add("@Category", SqlDbType.NVarChar).Value = a
                   ElseIf drpProCategory.Text = "Cross Functional Courses" Then
                       a = 2
                       DBCmd.Parameters.Add("@Category", SqlDbType.NVarChar).Value = a
                   ElseIf drpProCategory.Text = "Functional Courses (online)" Then
                       a = 3
                       DBCmd.Parameters.Add("@Category", SqlDbType.NVarChar).Value = a
                   ElseIf drpProCategory.Text = "Fluor University Functional Courses (instructor-led)" Then
                       a = 4
                       DBCmd.Parameters.Add("@Category", SqlDbType.NVarChar).Value = a
                   ElseIf drpProCategory.Text = "Local Functional Courses (instructor-led)" Then
                       a = 5
                       DBCmd.Parameters.Add("@Category", SqlDbType.NVarChar).Value = a
                   ElseIf drpProCategory.Text = "External Courses" Then
                       a = 6
                       DBCmd.Parameters.Add("@Category", SqlDbType.NVarChar).Value = a
                   ElseIf drpProCategory.Text = "Other Courses" Then
                       a = 5
                       DBCmd.Parameters.Add("@Category", SqlDbType.NVarChar).Value = a
                   End If
                   DBCmd.Parameters.Add("@Duration", SqlDbType.NVarChar).Value = txtProDuration.Text
                   DBCmd.ExecuteNonQuery()
                   lblProMessage.Text = "Your Proposed Plan was sent for approval"
                   If lblProMessage.Text = "Your Proposed Plan was sent for approval" Then
                       lblProMessage.Text = ""
                       panelAdd.Visible = False
                   End If

System.Data.SqlClient.SqlException: Cannot insert the value NULL into column 'Status', table 'TestSQL.dbo.tblCourses_13514'; column does not allow nulls. INSERT fails. The statement has been terminated. at System.Data.SqlClient.SqlConnection.OnError(SqlException exception, Boolean breakConnection) at System.Data.SqlClient.SqlInternalConnection.OnError(SqlException exception, Boolean breakConnection) at System.Data.SqlClient.TdsParser.ThrowExceptionAndWarning(TdsParserStateObject stateObj) at System.Data.SqlClient.TdsParser.Run(RunBehavior runBehavior, SqlCommand cmdHandler, SqlDataReader dataStream, BulkCopySimpleResultSet bulkCopyHandler, TdsParserStateObject stateObj) at System.Data.SqlClient.SqlCommand.FinishExecuteReader(SqlDataReader ds, RunBehavior runBehavior, String resetOptionsString) at System.Data.SqlClient.SqlCommand.RunExecuteReaderTds(CommandBehavior cmdBehavior, RunBehavior runBehavior, Boolean returnStream, Boolean async) at System.Data.SqlClient.SqlCommand.RunExecuteReader(CommandBehavior cmdBehavior, RunBehavior runBehavior, Boolean returnStream, String method, DbAsyncResult result) at System.Data.SqlClient.SqlCommand.InternalExecuteNonQuery(DbAsyncResult result, String methodName, Boolean sendToPipe) at System.Data.SqlClient.SqlCommand.ExecuteNonQuery() at ASP.home_aspx.btnProSubmit_Click(Object sender, EventArgs e) in C:\Documents and Settings\oca14625\Desktop\TRYING3\HOME.aspx:line 93