IPB WARNING [2] preg_match() [function.preg-match]: Compilation failed: repeated subpattern is too long at offset 19117 (Line: 168 of /sources/classes/class_session.php)

if ( preg_match( '/('.implode( '|', $this->bot_safe ) .')/i', $_SERVER['HTTP_USER_AGENT'], $match ) )
            {
                $DB->simple_construct( array( 'select' => '*',
                                              'from'   => 'groups',
                                              'where'  =>" g_id=".intval($ibforums->vars['spider_group'])
                                     )      );
                $DB->simple_exec();
            
                $group = $DB->fetch_row();
        
                foreach ($group as $k => $v)
                {
                    $this->member[ $k ] = $v;
                }
                
                $this->member['restrict_post']    = 1;
                $this->member['g_use_search']     = 0;
                $this->member['g_email_friend']   = 0;
                $this->member['g_edit_profile']   = 0;
                $this->member['g_use_pm']         = 0;
                $this->member['g_is_supmod']      = 0;
                $this->member['g_access_cp']      = 0;
                $this->member['g_access_offline'] = 0;
                $this->member['g_avoid_flood']    = 0;
                $this->member['id']               = 0;
                
                $ibforums->perm_id       = $this->member['g_perm_id'];
                   $ibforums->perm_id_array = explode( ",", $ibforums->perm_id );
                   $ibforums->session_type  = 'cookie';
                   $ibforums->is_bot        = 1;
                   $this->session_id        = "";
                   
                   $agent = trim($match[0]);
                   
                   //-----------------------------------------
                   // Using lofi?
                   //-----------------------------------------
                   
                   if ( strstr( $_SERVER['PHP_SELF'], 'lofiversion' ) )
                   {
                       $qstring = "Lo-Fi: ".str_replace( "/", "", strrchr( $_SERVER['PHP_SELF'], "/" ) );
                   }
                   else
                   {
                       $qstring = str_replace( "'", "", $_SERVER['QUERY_STRING']);
                   }
                   
                   if ( $ibforums->vars['spider_visit'] )
                   {
                       $DB->do_shutdown_insert( 'spider_logs', array (
                                                                    'bot'          => $agent,
                                                                    'query_string' => $qstring,
                                                                    'ip_address'   => $_SERVER['REMOTE_ADDR'],
                                                                    'entry_date'   => time(),
                                                        )        );
                   }
                   
                   if ( $ibforums->vars['spider_active'] )
                   {
                       $DB->simple_construct( array( 'delete' => 'sessions',
                                                  'where'  => "id='".$agent.'='.str_replace('.','',$this->ip_address )."_session'"
                                         )      );
                    $DB->simple_shutdown_exec();
                
                       $this->create_bot_session($agent, $this->bot_map[ strtolower($agent) ]);
                   }
                   
                   return $this->member;
            }