diff --git a/ChangeLog b/ChangeLog
index 102e2cc89..53dc40009 100755
--- a/ChangeLog
+++ b/ChangeLog
@@ -10,6 +10,7 @@ $Source$
     * config.inc.php, libraries/common.lib.php,
       libraries/config_import.lib.php: Support for SHA1 function (RFE
       #971703).
+    * main.php: Possible undefined variable.
 
 2004-06-09 Alexander M. Turek  <me@derrabus.de>
     * libraries/config_import.lib.php: The default settings should be merged.
diff --git a/main.php b/main.php
index 33177e771..29f7ea6b0 100644
--- a/main.php
+++ b/main.php
@@ -650,7 +650,7 @@ if (count($available_themes_choices)>1) {
                 <?php
                     for($i=0;$i<count($available_themes_choices);$i++){
                         echo '<option value="' . $available_themes_choices[$i] . '"';
-                        if ($available_themes_choices[$i] == $theme) {
+                        if (isset($theme) && $available_themes_choices[$i] == $theme) {
                             echo ' selected="selected"';
                             $theme_selected = TRUE;
                         }