New York--Another day, another media company warning of lower first-quarter earnings. But this one surprised Wall Street analysts: Dow Jones & Co. Inc., publisher of The Wall Street Journal, which is a major destination for b-to-b advertisers, said Wednesday it expects to report earnings of between 16 cents and 20 cents a share, down from 88 cents a year ago. The company said advertising in The Journal was down 31% in February, compared with a year earlier. At the same time, Dow Jones warned that it will lay off a small percentage of its 8,550 employees. Dow Jones has been hit by costs associated with its foray into the online financial data business.