You need to work backwards since the act of deleting a table reduces the number of tables in the document.
Sub RemoveTables2()
Dim i As Integer
For i = ActiveDocument.Tables.Count To 2 Step -2
ActiveDocument.Tables(i).Delete
Next i
End Sub

PS. The code you posted is erroring because you are missing the word 'For' in the front of the 'Each ...' line