The "Permission denied" your script is reporting in case of a failed request probably doesn't mean much, as you're reporting $! in

         print "failed response $!<BR>\n";
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The value of $! most likely is just some leftover unrelated (local) system error, not the reason the LWP request failed...

I suspect you rather want something like this to report the actual HTTP status code/message (which might provide a better hint at what's going wrong):

      $response = $ua->request($request);
      if ( $response->is_success ) {
         # ...
      } else {
         print $response->status_line, "\n";
      }
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