Creating an upload field for my module

Hello

I'm sorry to post here, but i didn't find help on the french forum :s

I'm playing with Drupal since 3 months, and i'm trying to build a carousel module using jquery, but I've got some probleme ton use the drupal uploading function.

First I've activated the upload module

Next I've fill the informations about the Files system path in Admin>Site config>File system to

tmp folder:
sites/default/tmp

Third I've build my field for my user in .module

function carousel_form(& $node){

...

  $form['#attributes'] = array('enctype' => "multipart/form-data");
	$form['picture_upload'] = array(
	'#type'=> 'file',
	'#title' => 'Image',
	'#size' => 50,
	'#description' => t("Select you imagel."),
	);
		
	$form['submit'] = array(
	'#type' => 'submit',
	'#value' => 'Upload'
	); 
}

and the function to upload :

function carousel_form_submit(&$form, &$form_state) {
	
	$validators=array();
  if ($file = file_save_upload('picture_upload', $validators)) {
  	  drupal_set_message($nom_fichier.' a été uploadé.');
    }
    else
    {
        drupal_set_message($nom_fichier."n'a pas été uploadé !");
    }
}

When i try to upload nothing appends :s
I've print the $_Files :
Array ( [files] => Array ( [name] => Array ( [picture_upload] => 03.jpg [upload] => ) [type] => Array ( [picture_upload] => image/jpeg [upload] => ) [tmp_name] => Array ( [picture_upload] => C:\Windows\Temp\php66F8.tmp [upload] => ) [error] => Array ( [picture_upload] => 0 [upload] => 4 ) [size] => Array ( [picture_upload] => 169794 [upload] => 0 ) ) )

Please could you help me ?

Best regards