Problem Wit Sp_execute SQL

I have to make a large number of updates (about 29k) so I generated teh update statements into a table and am trying to sue sp_executesql to run them. Here is my code:

Declare @SQLState NVARCHAR(500)

Declare Code Cursor
for
select SQLState from updates
open Code
FETCH NEXT FROM Code
into @SQLState
While @@fetch_Status = 0
Begin
Exec sp_executesql @SQLState

FETCH NEXT FROM Code
END

CLOSE Code
DEALLOCATE Code

IT appears to run succesfully, but the updates never happen - I get the following results for each update line:

UPDATE REEmployeeEvent SET UpdatedByEmployeeID= '00013' Where UpdatedByEmployeeID='00279'

(1 row(s) affected)

(0 row(s) affected)

Any ideas what I am doing wrong?

BTW - If I run the statements manually, they do work.

Thanks for any help!