diff --git a/admin/health.php b/admin/health.php
index d6877e0c908..10955ae8705 100644
--- a/admin/health.php
+++ b/admin/health.php
@@ -7,7 +7,8 @@
     define('SEVERITY_SIGNIFICANT', 'significant');
     define('SEVERITY_CRITICAL',    'critical');
 
-    $resetsesserrorcounter = optional_param( 'resetsesserrorcounter' );
+    $resetsesserrorcounter = optional_param('resetsesserrorcounter', 0, PARAM_BOOL);
+    $solution              = optional_param('solution', 0, PARAM_SAFEDIR); //in fact it is class name alhanumeric and _
 
     require_login();
     if (!isadmin()) {
@@ -83,9 +84,7 @@ dd.solution li {
 </style>
 STYLES;
 
-    $solution = optional_param('solution', NULL);
-
-    if(!empty($solution) && class_exists($solution)) {
+    if(strpos($solution, 'problem_') === 0 && class_exists($solution)) {
         health_print_solution($solution);
     }
     else {
diff --git a/admin/index.php b/admin/index.php
index d0a7a0f54de..2967841e156 100644
--- a/admin/index.php
+++ b/admin/index.php
@@ -1,23 +1,23 @@
 <?php // $Id$
 
 /// Check that config.php exists, if not then call the install script
-    if (!file_exists("../config.php")) {
+    if (!file_exists('../config.php')) {
         header('Location: ../install.php');
         die;
     }
    
-    require_once("../config.php");
-    include_once("$CFG->dirroot/lib/adminlib.php");  // Contains various admin-only functions
+    require_once('../config.php');
+    include_once($CFG->dirroot.'/lib/adminlib.php');  // Contains various admin-only functions
 
-    $id = optional_param('id', '', PARAM_ALPHANUM);
-    $confirmupgrade = optional_param('confirmupgrade','');
+    $id             = optional_param('id', '', PARAM_ALPHANUM);
+    $confirmupgrade = optional_param('confirmupgrade', 0, PARAM_BOOL);
 
 
 /// Check that PHP is of a sufficient version
 
-    if (!check_php_version("4.1.0")) {
-        $version = phpversion();
-        print_heading("Sorry, Moodle requires PHP 4.1.0 or later (currently using version $version)");
+    if (!check_php_version("4.1.0")) { //TODO: should we bump it up to 4.3.0??
+        $phpversion = phpversion();
+        print_heading("Sorry, Moodle requires PHP 4.1.0 or later (currently using version $phpversion)");
         die;
     }
 
diff --git a/admin/innodb.php b/admin/innodb.php
index 613b59cf988..e5cd323387b 100644
--- a/admin/innodb.php
+++ b/admin/innodb.php
@@ -1,6 +1,8 @@
 <?php
 
-   include('../config.php');
+   require_once('../config.php');
+
+   $confirm = optional_param('confirm', 0, PARAM_BOOL);
 
    require_login();
 
@@ -12,7 +14,7 @@
                 "Convert all tables from MYISAM to InnoDB");
 
 
-   if (!empty($confirm) and confirm_sesskey()) {
+   if ($confirm and confirm_sesskey()) {
 
        print_heading("Please be patient and wait for this to complete...");
 
@@ -24,7 +26,7 @@
        }
    } else {
        notice_yesno("Are you sure you want convert all your tables to the InnoDB format?", 
-                    "innodb.php?confirm=yes&sesskey=".sesskey(), "index.php");
+                    "innodb.php?confirm=1&sesskey=".sesskey(), "index.php");
    }
 
 ?>
diff --git a/admin/lang.php b/admin/lang.php
index 718c6803596..c87caf31255 100644
--- a/admin/lang.php
+++ b/admin/lang.php
@@ -1,8 +1,8 @@
 <?PHP // $Id$
 
-    require_once("../config.php");
+    require_once('../config.php');
 
-    $mode = optional_param('mode', '', PARAM_ALPHA);
+    $mode        = optional_param('mode', '', PARAM_ALPHA);
     $currentfile = optional_param('currentfile', 'moodle.php', PARAM_FILE);
 
     require_login();
diff --git a/admin/langdoc.php b/admin/langdoc.php
index 883281ca661..3f2304a8c68 100755
--- a/admin/langdoc.php
+++ b/admin/langdoc.php
@@ -9,6 +9,7 @@ Based on:   lang.php in 1.4.3+ release
 Thanks:     Jaime Villate for important bug fixing, koen roggemans for his job and all moodlers
             for intensive testing of this my first contribution
 */
+    require_once('../config.php');
 
     //
     // Some local configuration
@@ -21,8 +22,6 @@ Thanks:     Jaime Villate for important bug fixing, koen roggemans for his job a
                                     // or to filenames with filesize() == 0
     $filetemplate = '';             // template for new files, i.e. '$Id$';
 
-    require_once("../config.php");
-
     $currentfile = optional_param('currentfile', 'docs/README.txt', PARAM_PATH); 
 
     require_login();