diff --git a/Classes/PHPExcel/Writer/Excel2007.php b/Classes/PHPExcel/Writer/Excel2007.php
index 477d2db0..7823d0f3 100644
--- a/Classes/PHPExcel/Writer/Excel2007.php
+++ b/Classes/PHPExcel/Writer/Excel2007.php
@@ -193,7 +193,7 @@ class PHPExcel_Writer_Excel2007 implements PHPExcel_Writer_IWriter
 			// If $pFilename is php://output or php://stdout, make it a temporary file...
 			$originalFilename = $pFilename;
 			if (strtolower($pFilename) == 'php://output' || strtolower($pFilename) == 'php://stdout') {
-				$pFilename = @tempnam('./', 'phpxltmp');
+				$pFilename = @tempnam(PHPExcel_Shared_File::sys_get_temp_dir(), 'phpxltmp');
 				if ($pFilename == '') {
 					$pFilename = $originalFilename;
 				}