Conceding that the International Monetary Fund has made mistakes in the past, the IMF's new head promised to unveil reform proposals during the IMF's annual meetings next month in Prague. Horst Kohler, IMF managing director, said his efforts would be directed at focussing the fund on its core duties of preventing financial problems in a country from erupting into a full-blown crisis, and, where that fails, marshalling IMF resources in a more effective way.