just ad Sheets("sheet name").select to the code. then no matter what sheet you are on the code will always go to that sheet first.

Sub AddSheet()

    Sheets("listing").Select

    Application.ScreenUpdating = False
    Dim bottomA As Integer
    bottomA = Range("A" & Rows.Count).End(xlUp).Row
    Dim c As Range
    Dim ws As Worksheet
    For Each c In Range("A2:A" & bottomA)
        Set ws = Nothing
        On Error Resume Next
        Set ws = Worksheets(c.Value)
        On Error GoTo 0
        If ws Is Nothing Then
            Sheets("Sheet2").Select
            Sheets("Sheet2").Copy After:=Sheets(Sheets.Count)
            ActiveSheet.Name = c.Value
        End If
    Next c
    Application.ScreenUpdating = True
 End Sub