on submit html form with enctype multipart a compile warning generate

Question

In codeigniter when i submit a html form with image upload it give me an compile warning it run on local ok but on cpanel it give this error

A PHP Error was encountered

Severity: Compile Warning

Message: Unexpected character in input: '' (ASCII=14) state=0

Filename: lib/rules.php

Line Number: 889

Backtrace:

this is my form

<form action="<?= base_url();?>admin/test" method="post" enctype="multipart/form-data">
    <input type="file" name="staff_images">
    <input type="submit" value="submit">
</form>

and this is my method

public function test(){
    $this->load->view('test');
}