The following should work if the builkding block is stored in the document template
Code:
Private Sub CommandButton1_Click()
Dim oRng As Range
Me.Hide
If Me.OptionButton13.Value = True Then
Set oRng = ActiveDocument.Bookmarks("AddtValSites").Range
ActiveDocument.AttachedTemplate.BuildingBlockEntries("AddtValSiteBB").Insert _
Where:=oRng
End If
lbl_Exit:
Exit Sub
End Sub