Problemas com Post - PHP

<?php
    require_once '../system/config.php';
    require_once '../system/database.php';
?>

<?php
	define ( 'DB_HOSTNAME', 'localhost' );
	define ( 'DB_USERNAME', 'root' );
	define ( 'DB_PASSWORD', null );
	define ( 'DB_DATABASE', 'belas_frases' );
	define ( 'DB_PREFIX', 'bf' );
	

<?php
	
	// Deleta Registros
	function DBDelete($table, $where = null){
		$table 	= DB_PREFIX.'_'.$table;
		$where	= ($where) ? " WHERE {$where}" : null;
		
		$query 	= "DELETE FROM {$table}{$where}";
		return DBExecute($query);
	}
	
	// Altera Registros
	function DBUpDate($table, array $data, $where = null, $insertId = false){
		foreach ($data as $key => $value){
			$fields[] = "{$key} = '{$value}'";
		}
		
		$fields = implode(', ', $fields);
		
		$table 	= DB_PREFIX.'_'.$table;
		$where	= ($where) ? " WHERE {$where}" : null;
		
		$query 	= "UPDATE {$table} SET {$fields}{$where}";
		return DBExecute($query, $insertId);
	}
	
	// Ler Registros
	function DBRead($table, $params = null, $fields = '*'){
		$table 	= DB_PREFIX.'_'.$table;
		$params = ($params) ? " {$params}" : null;
		
		$query 	= "SELECT {$fields} FROM {$table}{$params}";
		$result	= DBExecute($query);
		
		if(!mysqli_num_rows($result))
			return false;
		else {
			while ($res = mysqli_fetch_assoc($result)){
				$data[] = $res;
			}
			
			return $data;
		}
	}
	
	// Grava Registros
	function DBCreate($table, array $data, $insertId = false){
		$table 	= DB_PREFIX.'_'.$table;
		$data 	= DBEscape($data);
		
		$fields	= implode(', ', array_keys($data));
		$values = "'".implode("', '", $data)."'";
		
		$query 	= "INSERT INTO {$table} ( {$fields} ) VALUES ( {$values} )";
		
		return DBExecute($query, $insertId);
	}
	
	// Executa Querys
	function DBExecute($query, $insertId = false){
		$link 	= DBConnect();
		$result = @mysqli_query($link, $query) or die(mysqli_error($link));
		
		if($insertId)
			$result = mysqli_insert_id($link);
		
		DBClose($link);
		return $result;
	}

	// Protege contra SQL Injection
	function DBEscape($data){
		$link = DBConnect();
		
		if(!is_array($data))
			$data = mysqli_real_escape_string($link, $data);
		else {
			$arr = $data;
			
			foreach ($arr as $key => $value){
				$key 	= DBEscape( $key );
				$value	= DBEscape( $value );
				
				$data[$key] = $value;
			}
		}
		
		DBClose($link);
		return $data;
	}

	// Fecha Conexão com MySQL
	function DBClose($link){
		@mysqli_close($link) or die(mysqli_error($link));
	}

	// Abre com Conexão com MySQL
	function DBConnect(){
		$link = @mysqli_connect(DB_HOSTNAME, DB_USERNAME, DB_PASSWORD, DB_DATABASE) or die(mysqli_connect_error());
		mysqli_set_charset($link, DB_CHARSET) or die(mysqli_error($link));
		
		return $link;
	}