The Windows version of ATK 2009.12 released earlier this week was missing one library component. Users experiencing installation problems should download the new build (3643) and re-install ATK.
We are very sorry to learn that the 3632 build of ATK 2009.12.0 failed to automatically install the proper Virtual C++ runtime environment, causing ATK to fail to start on Windows.
A new build (3643) has now been published, which amends this problems. We apologize for the inconvenience caused by this.
Linux users are not affected by this problem.
For more detailed information about ATK 2009.12 itself, see the release letter!