Error 500

[metalsa]

Hola estoy haciendo una pagina web en jsp y tengo un detalle.

en internet explorer 6.0 me sale este error:

java.lang.NumberFormatException: For input string: "null" at java.lang.NumberFormatException.forInputString(Num berFormatException.java:48) at java.lang.Integer.parseInt(Integer.java:468) at java.lang.Integer.parseInt(Integer.java:518) at _aplicaciones._innovacion._login._jspService(_logi n.java:213) [SRC:/Aplicaciones/innovacion/login.jsp:59] at com.orionserver[Oracle Application Server Containers for J2EE 10g (10.1.2.0.2)].http.OrionHttpJspPage.service(OrionHttpJspPage.ja va:56) at oracle.jsp.runtimev2.JspPageTable.service(JspPageT able.java:350) at oracle.jsp.runtimev2.JspServlet.internalService(Js pServlet.java:509) at oracle.jsp.runtimev2.JspServlet.service(JspServlet .java:413) at javax.servlet.http.HttpServlet.service(HttpServlet .java:853) at com.evermind[Oracle Application Server Containers for J2EE 10g (10.1.2.0.2)].server.http.ServletRequestDispatcher.invoke(Servl etRequestDispatcher.java:824) at com.evermind[Oracle Application Server Containers for J2EE 10g (10.1.2.0.2)].server.http.ServletRequestDispatcher.forwardInter nal(ServletRequestDispatcher.java:330) at com.evermind[Oracle Application Server Containers for J2EE 10g (10.1.2.0.2)].server.http.ServletRequestDispatcher.forward(Serv letRequestDispatcher.java:222) at com.evermind[Oracle Application Server Containers for J2EE 10g (10.1.2.0.2)].server.http.EvermindPageContext.forward(EvermindP ageContext.java:224) at _aplicaciones._innovacion._index._jspService(_inde x.java:58) [SRC:/Aplicaciones/innovacion/index.jsp:6] at com.orionserver[Oracle Application Server Containers for J2EE 10g (10.1.2.0.2)].http.OrionHttpJspPage.service(OrionHttpJspPage.ja va:56) at oracle.jsp.runtimev2.JspPageTable.service(JspPageT able.java:350) at oracle.jsp.runtimev2.JspServlet.internalService(Js pServlet.java:509) at oracle.jsp.runtimev2.JspServlet.service(JspServlet .java:413) at javax.servlet.http.HttpServlet.service(HttpServlet .java:853) at com.evermind[Oracle Application Server Containers for J2EE 10g (10.1.2.0.2)].server.http.ServletRequestDispatcher.invoke(Servl etRequestDispatcher.java:824) at com.evermind[Oracle Application Server Containers for J2EE 10g (10.1.2.0.2)].server.http.ServletRequestDispatcher.forwardInter nal(ServletRequestDispatcher.java:330) at com.evermind[Oracle Application Server Containers for J2EE 10g (10.1.2.0.2)].server.http.HttpRequestHandler.processRequest(Htt pRequestHandler.java:830) at com.evermind[Oracle Application Server Containers for J2EE 10g (10.1.2.0.2)].server.http.AJPRequestHandler.run(AJPRequestHandl er.java:224) at com.evermind[Oracle Application Server Containers for J2EE 10g (10.1.2.0.2)].server.http.AJPRequestHandler.run(AJPRequestHandl er.java:133) at com.evermind[Oracle Application Server Containers for J2EE 10g (10.1.2.0.2)].util.ReleasableResourcePooledExecutor$MyWorker.ru n(ReleasableResourcePooledExecutor.java:192) at java.lang.Thread.run(Thread.java:534)

Pero cuando lo pruebo con el Internet Explorer 7 no me sale ese error.

Aqui les dejo un poco del codigo de la pagina:

<%@page pageEncoding="UTF-8"%>
<%! private int a = 0;%>
<%! private int cont = 0;%>
<%! private int cont_silogin = 0;%>
<%! private int cont_faltan = 0;%>
<%! private int cont_invalido = 0;%>
<jsp:useBean id="conexion" class="Libinnovacion.conexion" />
<jsp:useBean id="validauser" class="Libinnovacion.valida" />
<jsp:useBean id="usuario" class="Libinnovacion.usuario" />
<%@ include file="lang/espanol.jsp" %>
<%
HttpSession actualSession = request.getSession(true); // Creamos la Session
//session.setMaxInactiveInterval(300); //Limite de Tiempo de Session
String login;
String qry;
String f = "";
String res[][];
String rec;
String ID;
login = "false";
String user = request.getParameter("user");
String pass = request.getParameter("pass");
String nomina = request.getParameter("nomina");
String sess = String.valueOf(actualSession.isNew());
if (actualSession.isNew()|| sess.equals("null") || sess == null) {
login = "false";
session.setAttribute("login", login);
} else {
if ((user != null) && (pass != null)) {
rec = String.valueOf(session.getAttribute("login"));
//out.print(rec);
if (rec.equals("true")) {
login = "true";
cont_silogin = 2;
} else {
if (a == 0) {
++a;
}
if ((user != null) && (pass != null)) {
conexion.conector2();
qry = validauser.Query(user);
conexion.Query(qry);
pass = pass.toUpperCase();
if (pass.equals(conexion.getmatriz(0, 0))) {
login = "true";
session.setAttribute("login", login);
cont = -1;
cont_silogin = 2;
usuario.setIdPerson(user.toUpperCase());
qry = usuario.getQryUser();
conexion.Query(qry);
session.setAttribute("IdP", String.valueOf(conexion.getmatriz(0, 0)));
ID = (String) session.getAttribute("IdP");
usuario.setTipo(ID);
qry = usuario.getQryUser();
conexion.Query(qry);
session.setAttribute("TypeUser", String.valueOf(conexion.getmatriz(0, 0)));
if (ID != null || ID.equals("null")) {
usuario.setDatosPerson(Integer.parseInt(ID));
qry = usuario.getQryUser();
//out.print(qry);
conexion.Query(qry);
res = conexion.getresultados();
int a = conexion.getcolum();
//out.print(a);
session.setAttribute("Nombre", res[0][0]);
session.setAttribute("Proceso", res[0][1]);
session.setAttribute("Uen", res[0][2]);
session.setAttribute("IdUen", res[0][3]);
session.setAttribute("Doc", "0");
session.setAttribute("Fin", "0");
usuario.setEmailPerson(Integer.parseInt(ID));
qry = usuario.getQryUser();
conexion.Query(qry);
session.setAttribute("Email", conexion.getmatriz(0,0));
usuario.setAuditorEmail(Integer.parseInt(ID));
qry = usuario.getQryUser();
conexion.Query(qry);
session.setAttribute("EmailAuditor", conexion.getmatriz(0,0));
usuario.setAuditorPerson(Integer.parseInt(ID));
qry = usuario.getQryUser();
conexion.Query(qry);
session.setAttribute("Auditor", conexion.getmatriz(0,0));
usuario.setAuditorNombre(Integer.parseInt(ID));
qry = usuario.getQryUser();
conexion.Query(qry);
session.setAttribute("AuditorNombre", conexion.getmatriz(0,0));
} else {
session.setAttribute("Nombre", "");
session.setAttribute("Proceso", "");
session.setAttribute("Uen", "");
session.setAttribute("IdUen", "");
session.setAttribute("Doc", "0");
session.setAttribute("Fin", "0");
session.setAttribute("Email", "");
session.setAttribute("EmailAuditor", "");
session.setAttribute("Auditor", "");
session.setAttribute("AuditorNombre", "");
}
conexion.desconectar();
} else {
cont++;
cont_invalido = 2;
}
} else {
cont_faltan = 2;
}
}
} else {
rec = String.valueOf(session.getAttribute("login"));
//out.print(rec);
if (rec.equals("true")) {
login = "true";
cont_silogin = 2;