Index: branches/version-2_4-dev/data/class/util/SC_Utils.php
===================================================================
--- branches/version-2_4-dev/data/class/util/SC_Utils.php	(revision 18564)
+++ branches/version-2_4-dev/data/class/util/SC_Utils.php	(revision 18565)
@@ -89,5 +89,6 @@
                 $eccube_html_dir = realpath($eccube_data_dir . DATA_DIR2HTML);
                 // htmlディレクトリとDOCUMENT_ROOTの相対パスがURL_DIR
-                $url_dir = preg_replace('|^' . preg_quote($_SERVER['DOCUMENT_ROOT']) . '|', '', $eccube_html_dir);
+                $document_root = realpath($_SERVER['DOCUMENT_ROOT']);
+                $url_dir = preg_replace('|^' . preg_quote($document_root) . '|', '', $eccube_html_dir);
                 // installページへのURLを生成。
                 $location = realpath('/' . $url_dir . '/install/index.php');