--- a/plugins/dump-zip.php
+++ b/plugins/dump-zip.php
@@ -7,7 +7,7 @@
 * @license http://www.gnu.org/licenses/gpl-2.0.html GNU General Public License, version 2 (one or other)
 */
 class AdminerDumpZip {
-	var $_filename, $_data = "";
+	var $filename;
 	
 	function dumpOutput() {
 		if (!class_exists('ZipArchive')) {
@@ -17,12 +17,13 @@
 	}
 	
 	function _zip($string, $state) {
-		$this->_data .= $string;
+		static $data = "";
+		$data .= $string;
 		if ($state & PHP_OUTPUT_HANDLER_END) {
 			$zip = new ZipArchive;
 			$zipFile = tempnam("", "zip");
 			$zip->open($zipFile, ZipArchive::OVERWRITE); // php://output is not supported
-			$zip->addFromString($this->_filename, $this->_data);
+			$zip->addFromString($this->filename, $data);
 			$zip->close();
 			$return = file_get_contents($zipFile);
 			unlink($zipFile);
@@ -32,7 +33,7 @@
 	}
 	
 	function dumpHeaders($identifier, $multi_table = false) {
-		$this->_filename = "$identifier." . ($multi_table && ereg("[ct]sv", $_POST["format"]) ? "tar" : $_POST["format"]);
+		$this->filename = "$identifier." . ($multi_table && ereg("[ct]sv", $_POST["format"]) ? "tar" : $_POST["format"]);
 		if ($_POST["output"] == "zip") {
 			header("Content-Type: application/zip");
 		}