datamapper problem

[eluser]Unknown[/eluser]
i m new to codeigniter.
as well as datamapper.
i have instaal datamapper recently bt facing the error

Fatal error: Cannot redeclare class DataMapper in D:\wamp\www\scrum\application\config\datamapper.php on line 29

i can't find out the solution.
any body pls help me.

[eluser]Farhan S. Basyaiban[/eluser]
set the autoload.php to:

$autoload['libraries'] = array('database', 'datamapper');