How to set which node a module loads on?
Check the current user having admin role, if you are using drupal superadmin, then check current logedin user's id equals 1.

&lt;?php
  function custommodule1_user($op, &amp;$edit, &amp;$account, $category = NULL) {
    global $user;
    if($op == 'update') {
      if (in_array("administrator", $user-&gt;roles) || $user-&gt;uid == 1) {
          // Show message that only for admin.
          // Do whatever you want do for admin.
          drupal_set_message('You are Administrator you are allowed to send data');
      }
      else {
          // Show message for author users.
          drupal_set_message('Sorry you do not have the rights to send data');
      }
    }
  }
?&gt;