diff --git a/filter/algebra/filter.php b/filter/algebra/filter.php
index c20a8e4c224..aa66f4abebb 100644
--- a/filter/algebra/filter.php
+++ b/filter/algebra/filter.php
@@ -40,7 +40,7 @@
 function string_file_picture_algebra($imagefile, $tex= "", $height="", $width="", $align="middle") {
   // Given the path to a picture file in a course, or a URL,
   // this function includes the picture in the page.
-  global $CFG;
+  global $CFG, $OUTPUT;
 
   $output = "";
   $origtex = $tex;
@@ -76,7 +76,7 @@ function string_file_picture_algebra($imagefile, $tex= "", $height="", $width=""
         $link = '/filter/algebra/displaytex.php?'.urlencode($tex);
         $action = new popup_action('click', $link, 'popup', array('height'=>300,'width'=>240));
     }
-    $output .= $OUTPUT->action_link($link, $anchortagcontents, $action, array('title'=>'TeX'));
+    $output .= $OUTPUT->action_link($link, $anchorcontents, $action, array('title'=>'TeX'));
     
   } else {
     $output .= "Error: must pass URL or course";
diff --git a/filter/tex/filter.php b/filter/tex/filter.php
index e77a8fae2ac..3992a614997 100644
--- a/filter/tex/filter.php
+++ b/filter/tex/filter.php
@@ -37,7 +37,7 @@
 /////////////////////////////////////////////////////////////////////////////
 
 function string_file_picture_tex($imagefile, $tex= "", $height="", $width="", $align="middle", $alt='') {
-    global $CFG;
+    global $CFG, $OUTPUT;
 
     if ($alt==='') {
         $alt = s($tex);
@@ -93,7 +93,7 @@ function string_file_picture_tex($imagefile, $tex= "", $height="", $width="", $a
             $link = '/filter/tex/displaytex.php?'.urlencode($tex);
             $action = new popup_action('click', $link, 'popup', array('height'=>300,'width'=>240));
         }
-        $output .= $OUTPUT->action_link($link, $anchortagcontents, $action, array('title'=>'TeX'));
+        $output .= $OUTPUT->action_link($link, $anchorcontents, $action, array('title'=>'TeX'));
     } else {
         $output .= "Error: must pass URL or course";
     }