diff -urpN ../drupal-5.2.orig/./includes/common.inc ./includes/common.inc
--- ../drupal-5.2.orig/./includes/common.inc	2007-09-27 11:14:40.000000000 +0200
+++ ./includes/common.inc	2007-09-27 12:20:45.000000000 +0200
@@ -2015,6 +2015,18 @@ function drupal_cron_run() {
     // Lock cron semaphore
     variable_set('cron_semaphore', time());
 
+    // Delete temporary tables
+    //echo "Deleting Temporary Tables";
+    $deltime=time()-(15*60);
+    //print "SELECT ttable FROM temporary_table WHERE creationdate < %d ($deltime)";
+    $result = db_query("SELECT ttable FROM {temporary_table} WHERE creationdate < %d", $deltime);
+    while ($temptable = db_fetch_object($result)) {
+      //print 'DROP TABLE '.$temptable->ttable;   
+      db_query('DROP TABLE '.$temptable->ttable);
+    }
+    //print "DELETE FROM temporary_table WHERE creationdate < %d ($deltime)";
+    db_query('DELETE FROM {temporary_table} WHERE creationdate < %d', $deltime);
+
     // Iterate through the modules calling their cron handlers (if any):
     module_invoke_all('cron');
 
diff -urpN ../drupal-5.2.orig/./includes/database.mysqli.inc ./includes/database.mysqli.inc
--- ../drupal-5.2.orig/./includes/database.mysqli.inc	2007-09-27 11:14:40.000000000 +0200
+++ ./includes/database.mysqli.inc	2007-09-27 15:03:37.000000000 +0200
@@ -338,13 +338,26 @@ function db_query_temporary($query) {
   $tablename = array_pop($args);
   array_shift($args);
 
-  $query = preg_replace('/^SELECT/i', 'CREATE TEMPORARY TABLE '. $tablename .' SELECT', db_prefix_tables($query));
+  // Check if table exist
+  $result=db_query("SHOW TABLES LIKE '$tablename'");
+  if(db_fetch_object($result)) {
+    // It does exist: Remove it
+    db_query("DROP TABLE $tablename");
+    db_query("DELETE FROM {temporary_table} where ttable like '$tablename'");
+  }
+
+  $query = preg_replace('/^SELECT/i', 'CREATE TABLE '. $tablename .' SELECT', db_prefix_tables($query));
   if (isset($args[0]) and is_array($args[0])) { // 'All arguments in one array' syntax
     $args = $args[0];
   }
   _db_query_callback($args, TRUE);
   $query = preg_replace_callback(DB_QUERY_REGEXP, '_db_query_callback', $query);
-  return _db_query($query);
+  $ret=_db_query($query);
+
+  // Insert into tt-table
+  db_query("INSERT INTO {temporary_table} (ttable, creationdate) VALUES ('%s', %d)", $tablename, time());
+
+  return $ret;
 }
 
 /**
diff -urpN ../drupal-5.2.orig/./includes/database.mysql.inc ./includes/database.mysql.inc
--- ../drupal-5.2.orig/./includes/database.mysql.inc	2007-09-27 11:14:40.000000000 +0200
+++ ./includes/database.mysql.inc	2007-09-27 15:03:42.000000000 +0200
@@ -358,13 +358,26 @@ function db_query_temporary($query) {
   $tablename = array_pop($args);
   array_shift($args);
 
-  $query = preg_replace('/^SELECT/i', 'CREATE TEMPORARY TABLE '. $tablename .' SELECT', db_prefix_tables($query));
+  // Check if table exist
+  $result=db_query("SHOW TABLES LIKE '$tablename'");
+  if(db_fetch_object($result)) {
+    // It does exist: Remove it
+    db_query("DROP TABLE $tablename");
+    db_query("DELETE FROM {temporary_table} where ttable like '$tablename'");
+  }
+
+  $query = preg_replace('/^SELECT/i', 'CREATE TABLE '. $tablename .' SELECT', db_prefix_tables($query));
   if (isset($args[0]) and is_array($args[0])) { // 'All arguments in one array' syntax
     $args = $args[0];
   }
   _db_query_callback($args, TRUE);
   $query = preg_replace_callback(DB_QUERY_REGEXP, '_db_query_callback', $query);
-  return _db_query($query);
+  $ret=_db_query($query);
+
+  // Insert into tt-table
+  db_query("INSERT INTO {temporary_table} (ttable, creationdate) VALUES ('%s', %d)", $tablename, time());
+
+  return $ret;
 }
 
 /**
diff -urpN ../drupal-5.2.orig/./modules/system/system.install ./modules/system/system.install
--- ../drupal-5.2.orig/./modules/system/system.install	2007-09-27 11:14:40.000000000 +0200
+++ ./modules/system/system.install	2007-09-27 11:27:55.000000000 +0200
@@ -154,6 +154,12 @@ function system_install() {
   switch ($GLOBALS['db_type']) {
     case 'mysql':
     case 'mysqli':
+      db_query("CREATE TABLE {temporary_table} (
+        aid int NOT NULL auto_increment,
+        ttable varchar(255) NOT NULL default '',
+        creationdate int NOT NULL default '0',
+        PRIMARY KEY (aid)
+      ) /*!40100 DEFAULT CHARACTER SET UTF8 */ ");
       db_query("CREATE TABLE {access} (
         aid int NOT NULL auto_increment,
         mask varchar(255) NOT NULL default '',