Index: branches/5.3.x/core/units/helpers/cat_dbitem_export_helper.php
===================================================================
diff -u -N -r15698 -r16111
--- branches/5.3.x/core/units/helpers/cat_dbitem_export_helper.php	(.../cat_dbitem_export_helper.php)	(revision 15698)
+++ branches/5.3.x/core/units/helpers/cat_dbitem_export_helper.php	(.../cat_dbitem_export_helper.php)	(revision 16111)
@@ -1,6 +1,6 @@
 <?php
 /**
-* @version	$Id: cat_dbitem_export_helper.php 15698 2013-02-19 11:33:17Z alex $
+* @version	$Id: cat_dbitem_export_helper.php 16111 2014-12-07 14:49:01Z alex $
 * @package	In-Portal
 * @copyright	Copyright (C) 1997 - 2009 Intechnic. All rights reserved.
 * @license      GNU/GPL
@@ -409,18 +409,22 @@
 
 			$file_helper->CheckFolder(EXPORT_PATH);
 
-			if ($event->Special == 'export') {
-				$write_mode = ($this->exportOptions['start_from'] == 0) ? 'w' : 'a';
-				$this->filePointer = fopen($this->getExportFilename(), $write_mode);
+			if ( $event->Special == 'export' ) {
+				$first_step = $this->exportOptions['start_from'] == 0;
+				$this->filePointer = fopen($this->getExportFilename(), $first_step ? 'w' : 'r+');
+
+				if ( !$first_step ) {
+					fseek($this->filePointer, 0, SEEK_END);
+				}
 			}
 			else {
 				$this->filePointer = fopen($this->getImportFilename(), 'r');
-			}
 
-			// skip UTF-8 BOM Modifier
-			$first_chars = fread($this->filePointer, 3);
-			if (bin2hex($first_chars) != 'efbbbf') {
-				fseek($this->filePointer, 0);
+				// skip UTF-8 BOM Modifier
+				$first_chars = fread($this->filePointer, 3);
+				if ( bin2hex($first_chars) != 'efbbbf' ) {
+					fseek($this->filePointer, 0);
+				}
 			}
 		}