problem with Eduardo Saito irule_limit_num_connections_googlebot

when RULE_INIT {
    Maximum number of concurrent HTTP requests
   set ::max_conc_http_requests 10
    Response content to send to a client which exceeds maximum number of concurrent HTTP requests
   set ::response_content "Some titleRetry later"
    Initialize an empty array to track bot IP addresses and current HTTP request counts
   array set ::active_clients { }
}
when HTTP_REQUEST {
    Look for bots by their User-Agent string
   switch -glob [string tolower [HTTP::header "User-Agent"]] {
      "*somebot*" -
      "*googlebot*" {
          set a variable to track that this is a bot
         set client_ip [IP::client_addr]
          Check if there is an existing entry in the array for this bot IP
         if { [info exists ::active_clients($client_ip)] } {
             Check if the bot is already has X number of 
            if {$::active_clients($client_ip) > $::max_conc_http_requests } {
                Log an entry to syslog-ng
               log local0. "Reject GOOGLEBOT IP $client_ip ($::active_clients($client_ip))"
                Send a 503 status back to client
               HTTP::respond 503 content $::response_content
            } else {
                 Bot IP exists in the array, but the client is under the max
                incr ::active_clients($client_ip)
            }
         } else {
             Bot IP doesn't exist in the array so add it
            set ::active_clients($client_ip) 1
         }
      }
   }
}
when HTTP_RESPONSE {
    Check if this is a response to a bot and that the IP exists in the array
   if { [info exists client_ip] and [info exists ::active_clients($client_ip)] } {
       Decrement the count in the array
      incr ::active_clients($client_ip) -1
      if { $::active_clients($client_ip) <= 0 } {
          Delete the array if there aren't any entries
         unset ::active_clients($client_ip)
      }
   }
}