Some imports take a long time to complete. However, in rare instances a table becomes temporarily "stuck," meaning that the table operations are not making any significant progress.
The Fusion Tables web application monitors import progress and reports what may be a stuck table. A dialog box gives you the choice whether to continuing waiting. If you choose not to wait, the "About this table" dialog will show the point at which an import or other operation became stuck, and how much additional progress has been made.