The self-written module in Drupal works strangely

Hello. For some reason, the module that uses the forms API in Drupal does not work correctly for me. The forms themselves are displayed normally, but when changing the settings and authorizing the user, Drupal displays a white page, which disappears after the update.
A white screen occurs when submitting data from other forms, such as when logging in or saving a configuration
Platform : Drupal 6.20
Module file content:
<?php

/**
 *@file
 *  
*/
/**
*  
*/
function formchecklinks_page(){
$output =drupal_get_form('formchecklinks_nameform');
return $output;
}
function formchecklinks_nameform(){
$form['#method']='post';
$form['task_name']=array(
    '#title'=>t(' '),
    '#type'=>'textfield',
    '#description'=>t('    '),
    '#size' => '30');
$form['email']=array(   
    '#title'=>t('Email'),
    '#type'=>'textfield',
    '#description'=>t(',     '),
    '#size' => '30',
    '#default_value' => $user->mail,
    '#required'=>TRUE);
$form['file']=array(    
    '#title'=>t('     CSV'),
    '#type'=>'file',
    '#description'=>t(',     '),
    '#required'=>TRUE
    );
$pereodic = array(
 '0'=>t(' '),
 '1'=>t(' '),
 '2'=>t('  2 '),
 '3'=>t('  3 '),
 '7'=>t('  '),
 );
$form['pereodic']=array(    
    '#title'=>t(' '),
    '#type'=>'radios',
    '#description'=>t('  '),
    '#options'=>$pereodic,
    '#required'=>TRUE,
    '#default_value'=>'0'
    );
$form['submit']=array (
    '#value'=>t(''),
    '#type'=>'submit', 
    );
    return $form;
}

Answer 1

$output = drupal_get_form(‘formchecklinks__index__nameform‘);

function formchecklinks_nameform(){
..
}

Check the titles. It is not clear what is meant by “but when changing the settings and authorizing the user, Drupal displays a white page that disappears after the update.” can you explain?