База данных заблокирована в vb.net при попытке обновить данные в vb.net

Здравствуйте, у меня есть простой способ обновить информацию о клиенте в одной из таблиц моей базы данных, однако, когда я пытаюсь обновить ее, возникает ошибка, говорящая о том, что база данных заблокирована. Я понятия не имею, как это исправить, потому что мои запросы на добавление и удаление работают нормально. Это сообщение об ошибке: System.Data.SQLite.SQLiteException: «база данных заблокирована база данных заблокирована"

Public Sub updateguest(ByVal sql As String)
    Try

        con.Open()
        With cmd
            .CommandText = sql
            .Connection = con
        End With

        result = cmd.ExecuteNonQuery
        If result > 0 Then
            MsgBox("NEW RECORD HAS BEEN UPDATED!")
            con.Close()


        Else
            MsgBox("NO RECORD HASS BEEN UPDATDD!")
        End If

    Catch ex As Exception
        MsgBox(ex.Message)
    Finally
        con.Close()
    End Try
End Sub

 Private Sub IbtnUpdate_Click(sender As Object, e As EventArgs) Handles ibtnUpdate.Click

    Dim usql As String = "UPDATE Customers SET fname = '" & txtFName.Text & "'" & "WHERE CustomerID ='" & txtSearchID.Text & "'"
    updateguest(usql)

End Sub

 Private Sub IbtnSearch_Click(sender As Object, e As EventArgs) Handles ibtnSearch.Click
    Dim sSQL As String
    Dim newds As New DataSet
    Dim newdt As New DataTable
    Dim msql, msql1 As String
    Dim con As New SQLiteConnection(ConnectionString)
    con.Open()
    msql = "SELECT * FROM Customers Where Fname Like '" & txtSearchName.Text & "%'"
    msql1 = "SELECT * FROM Customers Where CustomerID '" & txtSearchID.Text & "'"
    Dim cmd As New SQLiteCommand(msql, con)
    Dim cmd1 As New SQLiteCommand(msql1, con)

    Dim dt = GetSearchResults(txtSearchName.Text)
    dgvCustomerInfo.DataSource = dt

    Dim mdr As SQLiteDataReader = cmd.ExecuteReader()



    If mdr.Read() Then


        If txtSearchName.Text <> "" Then
            sSQL = "SELECT * FROM customers WHERE fname LIKE'" & txtSearchName.Text & "%'"

            Dim con1 As New SQLiteConnection(ConnectionString)
            Dim cmd2 As New SQLiteCommand(sSQL, con1)
            con1.Open()
            Dim da As New SQLiteDataAdapter(cmd2)
            da.Fill(newds, "customers")
            newdt = newds.Tables(0)
            If newdt.Rows.Count > 0 Then
                ToTextbox(newdt)
            End If
            dgvCustomerInfo.DataSource = newdt
            con1.Close()
            txtSearchID.Clear()

        ElseIf txtSearchID.Text <> "" Then
            sSQL = "SELECT * FROM customers WHERE CustomerID ='" & txtSearchID.Text & "'"

            Dim con2 As New SQLiteConnection(ConnectionString)
            Dim cmd2 As New SQLiteCommand(sSQL, con2)
            con2.Open()
            Dim da As New SQLiteDataAdapter(cmd2)
            da.Fill(newds, "customers")
            newdt = newds.Tables(0)
            If newdt.Rows.Count > 0 Then
                ToTextbox(newdt)
            End If
            dgvCustomerInfo.DataSource = newdt
            con2.Close()
            txtSearchName.Clear()


        End If

    Else
        MsgBox("No data found")
    End If


End Sub
   Private Sub IbtnDelete_Click(sender As Object, e As EventArgs) Handles ibtnDelete.Click
    Dim dsql As String = "DELETE FROM customers WHERE customerid = " & txtSearchID.Text & ""
    deleteme(dsql)
    updatedgv(dgvCustomerInfo)
    txtSearchID.Clear()
    txtSearchName.Clear()


End Sub
    Public Sub deleteme(ByVal sql As String)
    Try

        con.Open()
        With cmd
            .CommandText = sql
            .Connection = con
        End With

        result = cmd.ExecuteNonQuery
        If result > 0 Then
            MsgBox("NEW RECORD HAS BEEN DELTED!")
            con.Close()

        Else
            MsgBox("NO RECORD HASS BEEN DELTED!")
        End If

    Catch ex As Exception
        MsgBox(ex.Message)
    Finally
        con.Close()


    End Try
End Sub