I solved the import issue with
import usermodel.*;
Other problem: I can make a workbook ,not a sheet???
<para>
public class HelloExcel {
public static void main(String[] args)
throws IOException {
FileOutputStream bestand = new FileOutputStream(args[0]);
HSSFWorkbook wb = new HSSFWorkbook(); // is OK
HSSFSheet mysheet = wb.createSheet("mysheet"); // what is wrong with
this?