Use an update query.  Perhaps that would look like the following.
STEP 1:  BACKUP your data before attempting  the following.
STEP 2:  BACKUP your data before attempting  the following.

Without a backup you cannot restore the data if this does not work the way
you expect.

UPDATE Table1 INNER JOIN Table2
ON Table1.NameID = Table2.NameID
AND Table1.Name = Table2.Name
AND Table1.Date = Table2.Date
AND Table1.Items = Table2.Items
SET Table1.Errors = Table2.Errors

In the query grid (Design view)
-- add both tables
-- drag from each set of matching fields
-- add Table1.Errors to the fields
-- Select Query: Update query from the menu
-- TYPE the following in the update to "cell" under Table1.Errors
   [Table2].[Errors]
-- Select Query: RUN from the menu

If the two tables are identical in structure and contents then why do you
have two tables?  I am guessing that table2 is a subset of the records in
table1 and you only need table2 on a temporary basis to update table1.