FRANKFURT (Reuters) - German business software maker SAP warned on Thursday that it expected the negative impact of volatile exchange rates to worsen in the second quarter as the strong euro weighs on its financial results. The gains in the euro are causing headaches at many European companies that rely on revenues from abroad. The euro has climbed 2.3 percent against the U.S. dollar and nearly 6 percent against Japan's yen in the past six months.See More