diff --git a/lib/tablelib.php b/lib/tablelib.php
index 7534dddb322..9c7477483d3 100644
--- a/lib/tablelib.php
+++ b/lib/tablelib.php
@@ -551,7 +551,7 @@ class flexible_table {
             $alpha  = explode(',', get_string('alphabet'));
 
             // Bar of first initials
-
+         
             echo '<div class="initialbar firstinitial">'.get_string('firstname').' : ';
             if(!empty($this->sess->i_first)) {
                 echo '<a href="'.$this->baseurl.$this->request[TABLE_VAR_IFIRST].'=">'.$strall.'</a>';
@@ -559,7 +559,7 @@ class flexible_table {
                 echo '<strong>'.$strall.'</strong>';
             }
             foreach ($alpha as $letter) {
-                if ($letter == $this->sess->i_first) {
+                if (isset($this->sess->i_first) && $letter == $this->sess->i_first) {
                     echo ' <strong>'.$letter.'</strong>';
                 } else {
                     echo ' <a href="'.$this->baseurl.$this->request[TABLE_VAR_IFIRST].'='.$letter.'">'.$letter.'</a>';
@@ -576,7 +576,7 @@ class flexible_table {
                 echo '<strong>'.$strall.'</strong>';
             }
             foreach ($alpha as $letter) {
-                if ($letter == $this->sess->i_last) {
+                if (isset($this->sess->i_last) && $letter == $this->sess->i_last) {
                     echo ' <strong>'.$letter.'</strong>';
                 } else {
                     echo ' <a href="'.$this->baseurl.$this->request[TABLE_VAR_ILAST].'='.$letter.'">'.$letter.'</a>';