Index: branches/feature-module-update/data/class/SC_CampaignSession.php
===================================================================
--- branches/feature-module-update/data/class/SC_CampaignSession.php	(revision 15177)
+++ branches/feature-module-update/data/class/SC_CampaignSession.php	(revision 15355)
@@ -36,5 +36,5 @@
     /* キャンペーンページからの遷移情報を取得 */
     function getIsCampaign() {
-        return $_SESSION[$this->key][$this->is_campaign];
+        return isset($_SESSION[$this->key][$this->is_campaign]) ? $_SESSION[$this->key][$this->is_campaign] : false;
     }