Oil prices slipped on Tuesday, falling from two-month highs as concerns over a global economic slowdown crept back into the market, and a stronger dollar also weighed.   Prices sagged after a survey showed euro zone business expansion nearly stalled in January. That, coupled with disappointing U.S. factory orders data a day earlier, stoked worries about softer demand, analysts said.  Brent crude futures fell 53 cents to settle at $61.98 a barrel. They touched their highest level in more than two months at $63.63 the previous day. U.S. crude futures dropped 90 cents to settle at $53.66 a barrel, or down 1.7 percent.