diff --git a/op/op.AddDocument.php b/op/op.AddDocument.php
index ef0b66a95..cde7c547f 100644
--- a/op/op.AddDocument.php
+++ b/op/op.AddDocument.php
@@ -403,7 +403,7 @@ foreach($file_ary as $file) {
 	$controller->setParam('maxsizeforfulltext', $settings->_maxSizeForFullText);
 	$controller->setParam('defaultaccessdocs', $settings->_defaultAccessDocs);
 
-	if(!$document = $controller()) {
+	if(!($document = $controller())) {
 		$err = $controller->getErrorMsg();
 		if(is_string($err))
 			$errmsg = getMLText($err);