diff --git a/Classes/PHPExcel/Writer/Excel2007/Worksheet.php b/Classes/PHPExcel/Writer/Excel2007/Worksheet.php
index ee94805f76cf3fe67a83cf36105b298c140032a2..fbe84f570f2fe03a60862d7cbbf75ec54b40c4ad 100644
--- a/Classes/PHPExcel/Writer/Excel2007/Worksheet.php
+++ b/Classes/PHPExcel/Writer/Excel2007/Worksheet.php
@@ -765,10 +765,10 @@ class PHPExcel_Writer_Excel2007_Worksheet extends PHPExcel_Writer_Excel2007_Writ
 			$objWriter->writeAttribute('ref',	str_replace('$','',$range));
 
 			$columns = $pSheet->getAutoFilter()->getColumns();
-			if (validCountable($columns) && count($columns) > 0) {
+			if ((is_array($columns) || $columns instanceof Countable) && count($columns) > 0) {
 				foreach($columns as $columnID => $column) {
 					$rules = $column->getRules();
-					if (validCountable($rules) && count($rules) > 0) {
+					if ((is_array($rules) || $rules instanceof Countable) && count($rules) > 0) {
 						$objWriter->startElement('filterColumn');
 							$objWriter->writeAttribute('colId',	$pSheet->getAutoFilter()->getColumnOffset($columnID));