diff --git a/ChangeLog b/ChangeLog
index 7c180afdb68..b84c24045a3 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -39,6 +39,7 @@ For users:
 - Fix: No images into product description lines as PDF generation does
   not work with this.
 - New: [ task #326 ]: Add a numbering module to suggest automatically a product ref
+- Fix: Errors weren't being shown in customer's & supplier's orders
 
 For developers:
 - New: Add webservice for thirdparty creation and list.
diff --git a/htdocs/commande/fiche.php b/htdocs/commande/fiche.php
index f37cb5c78ac..3efad393732 100644
--- a/htdocs/commande/fiche.php
+++ b/htdocs/commande/fiche.php
@@ -7,6 +7,7 @@
  * Copyright (C) 2010-2012 Juanjo Menent         <jmenent@2byte.es>
  * Copyright (C) 2011      Philippe Grand        <philippe.grand@atoo-net.com>
  * Copyright (C) 2012      Christophe Battarel   <christophe.battarel@altairis.fr>
+ * Copyright (C) 2012      Marcos García         <marcosgdf@gmail.com>
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License as published by
@@ -517,20 +518,36 @@ else if ($action == 'setnote' && $user->rights->commande->creer)
 */
 else if ($action == 'addline' && $user->rights->commande->creer)
 {
-	$result=0;
+	$langs->load('errors');
+	$error = false;
 
+	if ((GETPOST('np_price') < 0) && (GETPOST('qty') < 0))
+    {
+        setEventMessage($langs->trans('ErrorBothFieldCantBeNegative', $langs->transnoentitiesnoconv('UnitPrice'), $langs->transnoentitiesnoconv('Qty')), 'errors');
+        $error = true;
+    }
 	if (! GETPOST('idprod') && GETPOST('type') < 0)
 	{
-		$mesg = '<div class="error">'.$langs->trans("ErrorFieldRequired",$langs->transnoentitiesnoconv("Type")).'</div>';
-		$result = -1 ;
+		setEventMessage($langs->trans('ErrorFieldRequired', $langs->transnoentitiesnoconv('Type')), 'errors');
+        $error = true;
 	}
-	if (! GETPOST('idprod') && GETPOST('np_price')=='')	// Unit price can be 0 but not ''
+	if (! GETPOST('idprod') && GETPOST('np_price') == '') // Unit price can be 0 but not ''
 	{
-		$mesg = '<div class="error">'.$langs->trans("ErrorFieldRequired",$langs->transnoentitiesnoconv("UnitPriceHT")).'</div>';
-		$result = -1 ;
+		setEventMessage($langs->trans($langs->trans('ErrorFieldRequired', $langs->transnoentitiesnoconv('UnitPrice'))), 'errors');
+        $error = true;
 	}
+	if (! GETPOST('qty') && GETPOST('qty') == '')
+    {
+        setEventMessage($langs->trans('ErrorFieldRequired', $langs->transnoentitiesnoconv('Qty')), 'errors');
+        $error = true;
+    }
+    if (! GETPOST('idprod') && (GETPOST('np_desc') == '') && (GETPOST('dp_desc') == ''))
+    {
+        setEventMessage($langs->trans('ErrorFieldRequired', $langs->transnoentitiesnoconv('Description')), 'errors');
+        $error = true;
+    }
 
-	if ($result >= 0 && GETPOST('qty') && ((GETPOST('np_price') != '' && (GETPOST('np_desc') || GETPOST('dp_desc'))) || GETPOST('idprod')))
+	if (!$error && GETPOST('qty') && ((GETPOST('np_price') != '' && (GETPOST('np_desc') || GETPOST('dp_desc'))) || GETPOST('idprod')))
 	{
 		// Clean parameters
 		$suffixe = GETPOST('idprod') ? '_predef' : '';
diff --git a/htdocs/fourn/commande/fiche.php b/htdocs/fourn/commande/fiche.php
index 03b54bcdc67..793e3f67504 100644
--- a/htdocs/fourn/commande/fiche.php
+++ b/htdocs/fourn/commande/fiche.php
@@ -5,6 +5,7 @@
  * Copyright (C) 2005-2012 Regis Houssin        <regis@dolibarr.fr>
  * Copyright (C) 2010-2012 Juanjo Menent        <jmenent@2byte.es>
  * Copyright (C) 2011      Philippe Grand       <philippe.grand@atoo-net.com>
+ * Copyright (C) 2012      Marcos García        <marcosgdf@gmail.com>
  *
  * This	program	is free	software; you can redistribute it and/or modify
  * it under	the	terms of the GNU General Public	License	as published by
@@ -169,7 +170,36 @@ else if ($action == 'reopen' && $user->rights->fournisseur->commande->approuver)
  */
 else if ($action == 'addline' && $user->rights->fournisseur->commande->creer)
 {
-    if (($_POST['qty'] || $_POST['pqty']) && (($_POST['pu'] && ($_POST['np_desc'] || $_POST['dp_desc'])) || $_POST['idprodfournprice']))
+    $langs->load('errors');
+    $error = false;
+
+    if ($_POST['pu'] < 0 && $_POST['qty'] < 0)
+    {
+        setEventMessage($langs->trans('ErrorBothFieldCantBeNegative', $langs->transnoentitiesnoconv('UnitPrice'), $langs->transnoentitiesnoconv('Qty')), 'errors');
+        $error = true;
+    }
+    if (empty($_POST['idprodfournprice']) && $_POST['type'] < 0)
+    {
+        setEventMessage($langs->trans('ErrorFieldRequired', $langs->transnoentitiesnoconv('Type')), 'errors');
+        $error = true;
+    }
+    if (empty($_POST['idprodfournprice']) && (! isset($_POST['pu']) || $_POST['pu']=='')) // Unit price can be 0 but not ''
+    {
+        setEventMessage($langs->trans($langs->trans('ErrorFieldRequired', $langs->transnoentitiesnoconv('UnitPrice'))), 'errors');
+        $error = true;
+    }
+    if (empty($_POST['idprodfournprice']) && empty($_POST['np_desc']) && empty($_POST['dp_desc']))
+    {
+        setEventMessage($langs->trans('ErrorFieldRequired', $langs->transnoentitiesnoconv('Description')), 'errors');
+        $error = true;
+    }
+    if ((! isset($_POST['qty']) || $_POST['qty'] == ''))
+    {
+        setEventMessage($langs->trans('ErrorFieldRequired', $langs->transnoentitiesnoconv('Qty')), 'errors');
+        $error = true;
+    }
+
+    if (!$error && (($_POST['qty'] || $_POST['pqty']) && (($_POST['pu'] && ($_POST['np_desc'] || $_POST['dp_desc'])) || $_POST['idprodfournprice'])))
     {
         if ($object->fetch($id) < 0) dol_print_error($db,$object->error);
         if ($object->fetch_thirdparty() < 0) dol_print_error($db,$object->error);
@@ -223,7 +253,6 @@ else if ($action == 'addline' && $user->rights->fournisseur->commande->creer)
             if ($idprod == -1)
             {
                 // Quantity too low
-                $langs->load("errors");
                 $mesg='<div class="error">'.$langs->trans("ErrorQtyTooLowForThisSupplier").'</div>';
             }
         }
@@ -288,9 +317,9 @@ else if ($action == 'addline' && $user->rights->fournisseur->commande->creer)
             unset($localtax1_tx);
             unset($localtax2_tx);
         }
-        else if (empty($mesg))
+        else
         {
-            $mesg='<div class="error">'.$object->error.'</div>';
+            $mesgs[] ='<div class="error">'.$object->error.'</div>';
         }
     }
 }
@@ -1803,7 +1832,6 @@ if ($id > 0 || ! empty($ref))
     }
 }
 
-
 // End of page
 llxFooter();