Typo, mFolderAdditionsHandler should read with
deletedItemsFolder.Items.ItemAdd as below:


public void mFolderAdditionsHandler()
{

//mb
//Add Sent Items Folder Watch
Outlook.MAPIFolder sentItemsFolder =
Globals.ThisAddIn.Application.GetNamespace("MAPI") .GetDefaultFolder(Microsoft.Office.Interop.Outlook .OlDefaultFolders.olFolderSentMail);
sentItemsFolder.Items.ItemAdd += new
Microsoft.Office.Interop.Outlook.ItemsEvents_ItemA ddEventHandler(Items_ItemAdd);

//Add Deleted Items Folder Watch
Outlook.MAPIFolder deletedItemsFolder =
Globals.ThisAddIn.Application.GetNamespace("MAPI") .GetDefaultFolder(Microsoft.Office.Interop.Outlook .OlDefaultFolders.olFolderDeletedItems);
deletedItemsFolder.Items.ItemAdd += new
Microsoft.Office.Interop.Outlook.ItemsEvents_ItemA ddEventHandler(Items_ItemAdd);
}