A few critical bugs found their way into Adobe's latest updates for Lightroom and Camera Raw affecting BOTH Mac and Windows platforms. As a result they have pulled the Lightroom 1.4 and Camera Raw 4.4 updates from the site and are recommending that you downgrade to the prior versions until the issues are resolved. For more information see their post at Lightroom Journal: Important Lightroom 1.4 and Camera Raw 4.4 Update