Problem with GROUP BY

When I try to execute the code below i get error message group by error

SELECT manifest_n, bill_of_la, release_no, frm_acct, source, source_id, sum(units) as totat FROM SERVICE WHERE manifest_n=2512 AND bill_of_la="158401" GROUP BY service.release_no INTO CURSOR mytotla ORDER BYrelease_no

If anyone can spot the problem I would appreciate a heads up

Thanks Jerry

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