diff --git a/op/op.SetExpires.php b/op/op.SetExpires.php
index c29ecb445..b32b97c0d 100644
--- a/op/op.SetExpires.php
+++ b/op/op.SetExpires.php
@@ -42,7 +42,8 @@ if ($document->getAccessMode($user) < M_READWRITE) {
 	UI::exitError(getMLText("document_title", array("documentname" => $document->getName())),getMLText("access_denied"));
 }
 
-$expires = ($_POST["expires"] == "true") ? mktime(0,0,0, sanitizeString($_POST["expmonth"]), sanitizeString($_POST["expday"]), sanitizeString($_POST["expyear"])) : false;
if (!$document->setExpires($expires)){
+$expires = ($_POST["expires"] == "true") ? mktime(0,0,0, sanitizeString($_POST["expmonth"]), sanitizeString($_POST["expday"]), sanitizeString($_POST["expyear"])) : false;
+if (!$document->setExpires($expires)){
 	UI::exitError(getMLText("document_title", array("documentname" => $document->getName())),getMLText("error_occured"));
 }