iRule problem: what is the matter whith this iRule?

If you want to do something with the URI in a respond you need to set it as a variable in HTTP_REQUEST, something like:

request_URI = [HTTP::uri]

Then in the HTTP_RESPONSE you can check it using $request_URI.

However, if you are trying to do a redirect in HTTP_RESPONSE, I would assume that you really want to do it base on something the server sent, not based on a request the client sent. If you are doing something based on what the client sent, that would be done in HTTP_REQUEST.