error editing new customer

[itocinc]

New 1.5.5.1 installation. Created a new customer, then went to edit the customer and after clicking saved get the following error:

Notice: Error: Unknown column 'date_modified' in 'field list'
Error No: 1054
UPDATE s3t1_customer SET firstname = 'John', lastname = 'Doe', email = 'jdoe@mail.com', telephone = '212-222-2222', fax = '', newsletter = '1', customer_group_id = '1', status = '1', date_modified = NOW() WHERE customer_id = '2' in /home/itoncall/public_html/system/database/mysql.php on line 50

[opencart]

just saved it and works fine no errors!

add the column manually