executing a pattern on module install

Hi,
i'd like to execute a pattern whenever my module is enabled. i have tried a couple of solutions but cant seem to get either of them to execute the pattern.

i have a hook_enable() in my module which has the following code -

$p_name = 'pattern_name;
  patterns_load_components();
  $patterns = patterns_get_patterns(true);
  foreach($patterns as $id => $p){
    if($p->name == $p_name){
  	  $pattern = patterns_get_pattern($p->pid);
  	  break;
  	}
  }
  	
  if ($pattern == FALSE) {
    drupal_set_message("Unable to execute $p_name because the pattern was not found.",'error');
  }else{
    $params = array(
      'pid' => $pattern->pid,
      'confirm' => 1,
      'run-subpatterns' => 'first-update',
    );
   
    //execute the pattern
    patterns_execute_pattern($pattern, $params);  
  }

this looks to me like it should work, but it doesnt? any ideas?