Session Library doesn't work!!!???

[eluser]Unknown[/eluser]
All CI libraries, MVC, etc works fine, except that whenever I call the CI session library,
it shows empty blank page with title "Untitled Document".

So I was using native PHP sessions instead, does anyone knows what happens any how to solve it? Did I miss anything?
Now, I need to get it done with CI library instead asap for my project that is nearly due.

please HELP! Thank you so much!

Code:

$config['encryption_key'] = "KeyABCD";

the config part are all by default
$config['sess_cookie_name']        = 'ci_session';
$config['sess_expiration']        = 7200;
$config['sess_encrypt_cookie']    = TRUE;
$config['sess_use_database']    = FALSE;
$config['sess_table_name']        = 'ci_sessions';
$config['sess_match_ip']        = FALSE;
$config['sess_match_useragent']    = TRUE;
$config['sess_time_to_update']     = 300;