--- moodlelib.php.orig	2012-03-10 09:04:31.000000000 +0900
+++ moodlelib.php	2012-04-25 22:06:24.990603700 +0900
@@ -1946,6 +1946,12 @@
         $format = get_string('strftimedaydatetime', 'langconfig');
     }
 
+    if ($CFG->ostype == 'WINDOWS') {
+        if ($localewincharset = get_string('localewincharset', 'langconfig')) {
+            $format = textlib::convert($format, 'utf-8', $localewincharset);
+        }
+    }
+
     if (!empty($CFG->nofixday)) {  // Config.php can force %d not to be fixed.
         $fixday = false;
     } else if ($fixday) {
@@ -1985,8 +1991,7 @@
 
    if ($CFG->ostype == 'WINDOWS') {
        if ($localewincharset = get_string('localewincharset', 'langconfig')) {
-           $textlib = textlib_get_instance();
-           $datestring = $textlib->convert($datestring, $localewincharset, 'utf-8');
+           $datestring = textlib::convert($datestring, $localewincharset, 'utf-8');
        }
    }