error even after instantiating the class

[raamay]

hello everyone, i have a class for form validation as below:

<?php
defined( '_JEXEC' ) or die( 'Restricted access' );
 
require_once ( JPATH_BASE .DS.'includes'.DS.'defines.php' );
require_once ( JPATH_BASE .DS.'includes'.DS.'framework.php' );
require_once ( JPATH_BASE .DS.'configuration.php' );
 
$mainframe =& JFactory::getApplication('site');
$mainframe->initialise();
 
class Form
{
   var $values = array();
   var $errors = array(); 
   var $num_errors;  
 
   function Form(){
 
      if(isset($_SESSION['value_array']) && isset($_SESSION['error_array'])){
 
         $this->values = $_SESSION['value_array'];
         $this->errors = $_SESSION['error_array'];
         $this->num_errors = count($this->errors);
 
         unset($_SESSION['value_array']);
         unset($_SESSION['error_array']);
      }
      else{
 
         $this->num_errors = 0;
      }
   }
 
   function setValue($field, $value){
 
      $this->values[$field] = $value;
 
   }
 
   function setError($field, $errmsg){
 
      $this->errors[$field] = $errmsg;
 
      $this->num_errors = count($this->errors);
 
   }
 
   function value($field){
 
      if(array_key_exists($field,$this->values)){
 
         return stripslashes($this->values[$field]);
 
      }else{
 
         return "";
 
      }
 
   }
 
   function error($field){
 
      if(array_key_exists($field,$this->errors)){
 
         return "<font size=\"1\" color=\"#ff0000\">".$this->errors[$field]."</font>";
 
      }else{
 
         return "";
 
      } 
 
   function getErrorArray(){
 
      return $this->errors;
 
   }
}
}
 

Now i have instantiated the class in joomla model like below:

<?php
defined( '_JEXEC' ) or die( 'Restricted access' );
JLoader::register('Form', dirname(__FILE__) . DS .'form.php');
 
if (class_exists('Form')) {
    $form = new Form();
    }
jimport('joomla.application.component.model');
 
Class JobsModelJobs extends JModel {
.
.
.
.
function validate(){
      global $form;
 
      $name = JRequest::getVar('name', 'POST');
      $email = JRequest::getVar('email', 'POST');
 
      $field = "name";
      if(!$name || strlen($name = trim($name)) == 0){
         $form->setError($field, "Please enter your name!");
 
      }
      $_SESSION['value_array'] = JRequest::get( 'POST' );
      $_SESSION['error_array'] = $form->getErrorArray();
 
   }       
}
 

I have tried to invoke the function setError() and getErrorArray() of the form class in my current function but i get the error "Fatal error: Call to a member function setError() on a non-object in".

Please tell me why the function is not recognized by the current class even after instantiating?

[Rabbit]

It might be because you redeclare your form variable in your validate function.