First off, declaring a Range does indeed use a Start, and and End.  However,
Start:=tbl3.Cell(13, 1) is NOT a valid value for a Range value.  Thus:  Type
Mis-match

Start:=    needs to be a NUMBER

tbl3.Cell(13, 1) is NOT a number, it is a cell.

Second, I do not know what your other code is like, but I would guess that it
could probably run better using objects.  This is a simple example.  An
active document, and an already open (but NOT active) document named "Yadda".
The code makes a table object of the third table in the active document, and
a table object in the target document ("Yadda").

Dim ThisDoc As Document
Dim ThatDoc As Document
Dim SourceTable As Table
Dim TargetTable As Table

Set ThisDoc = ActiveDocument
Set ThatDoc = Documents("Yadda")
Set SourceTable = ThisDoc.Tables(3)
Set TargetTable = ThatDoc.Tables(2)

Now you can just transfer contents from one table to the other.  You do not
have to make "Yadda" active; you do not have to copy and paste.

TargetTable.Cell(2, 2).Range.Text =
   SourceTable.Cell(5,2).Range.Text

This makes Tables(2).Cell(2,2) in "Yadda" the contents of Tables(3).Cell(5,2)
in the active document.

This is a very simple example.  You can also use cell objects and dump stuff
even mor eefficiently.

NOTE:  you will need to strip off end-of-cell markers using the Range of the
cells, if you want a perfect copy.