use mootools shipped by debian, rather than the zoneminder included mootools.
http://bugs.debian.org/585590

Index: zoneminder/web/skins/classic/includes/functions.php
===================================================================
--- zoneminder.orig/web/skins/classic/includes/functions.php	2011-07-22 03:40:07.000000000 -0700
+++ zoneminder/web/skins/classic/includes/functions.php	2011-09-28 07:03:59.582380536 -0700
@@ -62,9 +62,8 @@
 <?php
     }
 ?>
-  <script type="text/javascript" src="tools/mootools/mootools-core.js"></script>
-  <script type="text/javascript" src="tools/mootools/mootools-more.js"></script>
-  <script type="text/javascript" src="js/mootools.ext.js"></script>
+  <script type="text/javascript" src="/javascript/mootools/mootools-core-nc.js"></script>
+  <script type="text/javascript" src="/javascript/mootools/mootools-more-nc.js"></script>
   <script type="text/javascript" src="js/logger.js"></script>
   <script type="text/javascript" src="js/overlay.js"></script>
 <?php
