[eluser]Clooner[/eluser]
[quote author="alberta" date="1249821157"]sorry, i had put wrong view page.. i've also used form_validation, but still not showing error message

[/quote]
It seems that you mess up the order somehow.
It should look like something like this In your controller
Code:
function edit_plan($plan_id)
{
$this->load->library("form_validation");
$fields=array(array('field' => 'commit',
'rules' => 'trim|required'));
$this->form_validation->set_rules($fields);
if ($this->form_validation->run())
{
// in case of success
// do your thing
// redirect to someplace
} else
{
// in case of failure
// actually you don't have to do anything here
}
//show the view file of the form including the error message here
}
And in your view
Code:
<?php echo form_error('commit'); ?>
<form name="editplan" action=" <?php /* same url as before */ ?> " method="post" >
<textarea class="text" cols="48" name="commit" style="height: 100px;" ><?php echo set_value('commit'); ?></textarea
<input value="Commit" type="button">
</form>
again use the form_validation library. It is a bad idea to use the validation library. Make sure you do everything in the correct order. The manual is very clear on how to use the form_validation library.