Send mail macro not working in Outlook 2013

I have been using the code below in a macro in Outlook 2003 to send a number of mail items selected in the Inbox at one time. The reason for doing this is that our accounts package outputs emails of customer statements into the inbox which in theory you then have to open up one at a time and send them individually. This macro allows us to select multiple emails and then just run the macro to send them.

Sub SendAll()
    Dim olkMsg As Outlook.MailItem, _
        intIndex As Integer
    For intIndex = Application.ActiveExplorer.Selection.Count To 1 Step -1
        Set olkMsg = Application.ActiveExplorer.Selection.Item(intIndex)
        olkMsg.Send
    Next
    Set olkMsg = Nothing
End Sub

However, we have just upgraded to Outlook 2013 and now the macro won't work. The error message "This method can't be used with an inline response mail item." appears and then when you go to Debug, "olkMsg.Send" is highlighted.

Can anyone provide alternative code to perform the same task that will work in Outlook 2013?