$this->db don't return errors

[eluser]Unknown[/eluser]
Using the last version 2.1.0 there is some situations where i can't find a way to make the system to output the error to me.

PHP and Database errors seen to show without problems.

Code:

echo $Non_declared_variable //Show error
$this->db->select("column_not_in_db") //Show error
$this->db->selects("Anything"); //(selects instead of select)Show just a blank screen

I even tried to catch the error, but still give me a blank screen. Help anyone?
This also happened to another library used to send e-mails that i loaded using $this->library->load();

Edit:
This is the error CI give me in a older version i have here.

Code:

Fatal error: Call to undefined method CI_DB_postgre_driver::selects() in /home/storage/3/96/[...]/file.php on line 18