Matchbox HMVC autoload firephp library failed

[eluser]phoenixg[/eluser]
I installed BackendPro 0.6.1, it uses matchbox as HMVC solution, I want to use firephp to debug my code, but after I put Firephp.php and Fb.php files into system/application/libraries/ folder, and change config.php(autoload option to

Code:

$autoload['libraries'] = array('firephp','fb');

), and failure information appeared when I visit my site, the information is :

An Error Was Encountered
Unable to load the requested class: firephp

I found this thread: http://ellislab.com/forums/viewthread/65749/P390 discussed before, but I still couldn't figured out how to solve the problem. Did I put a wrong folder in?

[eluser]phoenixg[/eluser]
anybody help?