Method 'copy' Of Object '_worksheet' Failed

From the current open book, I'm opening a 2nd book, then copying all worksheets from the 2nd book that meet criteria, into 1st book, (in the same order), but am getting Method 'Copy' of object '_Worksheet' failed error. What am I doing wrong?
How to OVERWRITE worksheets?We'll be running the same process with new data, so also need to overwrite worksheets in 1st book.


Sub Build_Branch_File()
Dim FileName As String
Dim Wkb As Workbook
Dim Ws As Worksheet
Dim WNum As String
Dim Tnum As String
Dim RegionNo As Integer
Dim Original_Wb As Workbook


With Application
. ScreenUpdating = False
.EnableEvents = False
.DisplayAlerts = False
End With
Set Original_Wb = ThisWorkbook .........................