LM Paypal Button not display on page

Hi

LM Paypal Button not display on page. the following code is not working.

<?php
if (function_exists('lm_paypal_can_subscribe')) 
{
  $subid = 1;
  if (lm_paypal_can_subscribe ($subid)) 
{
    print 'Why not subscribe now? ' . lm_paypal_subscribe($subid,8);
  }
}
?>