Library - class file was not found - How to track error

[eluser]sanguina[/eluser]
Sort of bumping this.. but I have taken all care for creating library

1) Used uppercase for file name & class name.
2) Created a file called Phpass.php in application/library
3) Phpass.php contains a class Phpass which has a method hash($password)

but these two lines:

$this->load->library('phpass');
$password = $this->phpass->hash($password);

still give the error:

The phpass class file was not found.

What am i doing wrong ?
stuck here for the last 4 hours - pls pls pls help