Table not found problem

[RamiroS]

Hello. I'm building my own vB driven page and I'm getting a table doesn't exist error (error 1146) even though the table is there, is not broken, visible and editable through phpmyadmin.
Reading the forums I saw some people had this problem because broken files... I've updated to the latest vBulletin version (3.5.4) and the problem remains. What can be wrong with it? Thanks.

Here is the error:

Database error in vBulletin 3.5.4:

Invalid SQL:

	INSERT INTO mytable
		(pid,uid) 
			VALUES
		('0', '0');

MySQL Error  : Table 'db.mytable' doesn't exist
Error Number : 1146
Date         : Wednesday, July 12th 2006 @ 12:05:06 AM
Script       : http://www.myhost.com/forum/myscript.php
Referrer     : 
IP Address   : xxx.xxx.xxx.xxx
Username     : fdas
Classname    : vb_database

Here is my custom page:

PHP Code:

<?php
// ####################### SET PHP ENVIRONMENT ###########################
error_reporting(E_ALL & ~E_NOTICE);

// #################### DEFINE IMPORTANT CONSTANTS #######################
define('NO_REGISTER_GLOBALS', 1);
define('THIS_SCRIPT', 'agregar_noticias'); // change this depending on your filename

// ################### PRE-CACHE TEMPLATES AND DATA ######################
// get special phrase groups
$phrasegroups = array(

);

// get special data templates from the datastore
$specialtemplates = array(
    
);

// pre-cache templates used by all actions
$globaltemplates = array(
    'agregar_noticias',
);

// pre-cache templates used by specific actions
$actiontemplates = array(

);

// ######################### REQUIRE BACK-END ############################
require_once('./global.php');

// #######################################################################
// ######################## START MAIN SCRIPT ############################
// #######################################################################
$uid=$vbulletin->input->clean_gpc('r', 'uid', TYPE_UINT);
$pid=$vbulletin->input->clean_gpc('r', 'pid', TYPE_UINT);

$db->query_write("
    INSERT INTO " . TABLE_PREFIX . "mytable
        (pid,uid) 
            VALUES
        ('$pid', '$uid');
");


eval('print_output("' . fetch_template('agregar_noticias') . '");');
?>