Error Using UPDATE Statement

Hi,

I am relatively new to SQL. I am using SQL 2000. I am trying to
Update a field base in a criteria in a scond table.

UPDATE Tbl1
SET Tbl1.Row2 = '1'
WHERE Tbl1.Row1 =
(SELECT Tbl1.Row1
FROM Tbl2, Tbl1
WHERE Tbl2.Row1 = Tbl1.Row1 AND ({ fn
CURRENT_TIMESTAMP () } >= Tbl2.Row3))

Row 1 is the key between the two table. If I am doing only the select
below, I am getting the right value.

SELECT Tbl1.Row1
FROM Tbl2, Tbl1
WHERE Tbl2.Row1 = Tbl1.Row1 AND ({ fn
CURRENT_TIMESTAMP () } >= Tbl2.Row3)

When I am running the entire querry, I am getting this error:

Subquery returned more than 1 value. This is not permitted when the
subquery follows =, !=, <, <= , >, >= or when the subquery is used as
an expression.
The statement has been terminated.

What I am trying to do is to update a field in Tbl1 base on a date in
Tbl2. If the date is expire, I want to raise a flag, in Tbl1.

Thank you

Philippe