Worries over the economy and possible inflation cancelled out gains from dropping oil prices last week. Stock prices ended lower, with the Dow Jones industrial average falling 0.09 percent to 10,543.22 and the Nasdaq slumping 0.04 percent to 2,128.07. Wall Street was troubled by the Labor Department’s latest Producer Price Index report, which measures wholesale prices. That overshadowed an unexpected drop in crude-oil futures. But while the rise in wholesale prices hasn’t yet hit consumers to any great extent, it leaves many companies with tighter margins and reduced growth prospects. On the Big Board, Omnicom rose 0.6 percent to close at $82.08, while IPG rose 2.3 percent to end at $12.85. WPP, trading as American Depository Receipts on the Nasdaq, fell 3.4 percent, closing at $53.66.