U.S. Stocks Open Lower, Coca-Cola Weighs  NEW YORK (Reuters) - U.S. stocks opened lower on Wednesday  as Coca-Cola Co. &lt;A HREF="http://www.investor.reuters.com/FullQuote.aspx?ticker=KO.N target=/stocks/quickinfo/fullquote"&gt;KO.N&lt;/A&gt; upset sentiment by warning earnings for  the rest of the year would lag expectations, while concerns  about Hurricane Ivan and its effect on crude prices continued  to weigh on investors.