diff -r 2f9108930e47 -r d70552fc1a66 src/cm/media/js/site/f_text_view_frame.js
--- a/src/cm/media/js/site/f_text_view_frame.js	Fri May 11 16:50:30 2012 +0200
+++ b/src/cm/media/js/site/f_text_view_frame.js	Mon May 14 10:15:01 2012 +0200
@@ -20,14 +20,16 @@
 onInnerNorthPaneClose = function() {
   _setCookie('innerNorthPaneOpened', '0');
   $('#add_comment_btn').css('top', 63) ;
-  document.getElementById('text_view_comments').contentDocument.getElementById('the-toc').style.height = (parseInt(document.getElementById('text_view_comments').clientHeight) - 50).toString() + 'px';
+  if (document.getElementById('text_view_comments').contentDocument != null)
+    document.getElementById('text_view_comments').contentDocument.getElementById('the-toc').style.height = (parseInt(document.getElementById('text_view_comments').clientHeight) - 50).toString() + 'px';
   return true;
 }
 
 onInnerNorthPaneOpen = function() {
   _setCookie('innerNorthPaneOpened', '1');
   $('#add_comment_btn').css('top', 149) ;
-  document.getElementById('text_view_comments').contentDocument.getElementById('the-toc').style.height = (parseInt(document.getElementById('text_view_comments').clientHeight) - 50).toString() + 'px';
+  if (document.getElementById('text_view_comments').contentDocument != null)
+    document.getElementById('text_view_comments').contentDocument.getElementById('the-toc').style.height = (parseInt(document.getElementById('text_view_comments').clientHeight) - 50).toString() + 'px';
   return true;
 }