java.lang.ClassNotFoundException：jxl.read.biff.BiffException

In my J2EE web project, I have a simple JSP (HomeScreen.jsp) and a servlet class (HomeScreenServlet.java) behind it. This class is calling non-static method (PDFAwt1) from another class (PDFAwt) which in turn calls many other methods from many different classes, as usually happens. In my J2EE web project, I have a simple JSP (Ho