Saving Excel Files in ActionScript and Flex

In saving to an Excel (xls) file from Adobe Flex / Flash using ActionScript code, make sure to include
import com.as3xls.xls.ExcelFile;
import com.as3xls.xls.Sheet;
Then, make sure to require Flash Player 10.0.0 or higher or the application will not build in Flex Builder 4.  Project->Properties->Flex Compiler -> Check Require Flash Player version: 10 0 0.
Wire your event listener appropriately.
var [...]