1.a $this->member is from controller

1.b your views

          <fieldset>
            <legend><b>Categories:</b></legend>
            <div >
                <?php
                  $array = array();
                  $array = $this->member;
                  echo $this->partial('/login/categories.phtml', $array);
                ?>
            </div>
          </fieldset>


2. in categories.phtml as it runs on its own scope use this: $this-id coming from $array ($this->member)
<div id="opera" >

  <form method="post" action="/login/addcategories">
    <div>
      <?php

        echo $this->formHidden('id','', array() );
        echo $this->formHidden('clientid',$this->id, array() );

        echo $this->formLabel('id', 'Name: ', array('class'=>''));
        echo $this->formText('name','', array() );

        echo $this->formLabel('id', 'Text: ', array('class'=>''));
        echo $this->formText('text','', array() );

        echo $this->formSubmit('zoek', 'Add', array('class'=>'') );

      ?>
    </div>
  </form>

</div>