It's not really a surprise anymore, but the release said "weak household balance sheets and confidence, relatively tight financial conditions, and continued fiscal consolidation stand in the way of stronger growth" in the United States. Fiscal consolidation meaning the "fiscal cliff." In a blog post, Olivier Blanchard, the IMF's chief economist, said the U.S. must balance monetary accommodation and fiscal consolidation to maintain growth. So that's where the Federal Reserve's QE-infinity program comes in. And for Europe, "the “core” economies are expected to see low but positive growth throughout 2012–13. Most euro area “periphery” economies are likely to suffer a sharp contraction in 2012, constrained by tight fiscal policies and financial conditions, and to begin to recover only in 2013." And Spain and Italy's sovereign debt, banks and economy must stay under control.
For a quick rundown on the IMF's growth projections and fiscal outlook, I embedded two videos from the IMF's Youtube channel.
Source: IMF (Chapter 3: The Good, the Bad, and the Ugly: 100 Years of Dealing with Public Debt Overhangs)