Errors when saving node Im at a bit of a loss here, this error started happening when saving a new node, or updating an existing node.

It says The website encountered an unexpected error. Please try again later..

The error on the screen is...


  Notice: Undefined index: fid in file_field_update() (line 276 of
  C:\wamp\www\thelhp\modules\file\file.field.inc).
  
  Notice: Undefined index: fid in file_field_update() (line 302 of
  C:\wamp\www\thelhp\modules\file\file.field.inc).
  
  Notice: Undefined property: stdClass::$fid in file_usage_add() (line
  689 of C:\wamp\www\thelhp\includes\file.inc).
  
  PDOException: SQLSTATE[23000]: Integrity constraint violation: 1048 Le
  champ 'fid' ne peut être vide (null): INSERT INTO {file_usage} (fid,
  module, type, id, count) VALUES (:db_insert_placeholder_0,
  :db_insert_placeholder_1, :db_insert_placeholder_2,
  :db_insert_placeholder_3, :db_insert_placeholder_4); Array (
  [:db_insert_placeholder_0] => [:db_insert_placeholder_1] => file
  [:db_insert_placeholder_2] => node [:db_insert_placeholder_3] => 196
  [:db_insert_placeholder_4] => 1 ) in file_usage_add() (line 696 of
  C:\wamp\www\thelhp.co.uk\includes\file.inc).


I am now not able to create nodes, or update existing ones.

HOWEVER, after further testing, I have found that if I upload an image to the optional image field, nodes save and update just fine. When no image is uploaded, the errors show up. help! :-(
I had custom code in my module...

function custom_node_presave($node) {

  if(isset($node-&gt;field_gallery_images)) {
    $node-&gt;field_gallery_images[LANGUAGE_NONE][0]['alt']=$node-&gt;title;
    $node-&gt;field_gallery_images[LANGUAGE_NONE][0]['title']=$node-&gt;title;
  }

}


Commenting it out stopped the error