problem about directfb porting on uclinux with nios2

I ported directfb on uclinux with nios-linux-20090730.The compiling is successful.

But when i run programe base on directfb.I got this error.

~~~~~~~~~~~~~| DirectFB 1.2.7|~~~~~~~~~~~~~~~~~~~~~~~

(c) 2001-2008 The world wide DirectFB Open Source Community

(c) 2000-2004 Convergence (integrated media) GmbH

----------------------------------------------------------------

(*) DirectFB/Core: Single Application Core. (2010-06-30 01:23)

(!) DirectFB/core/system: No system found!

Could not initialize graphics driver directfb:

No (suitable) implementation found!

The problem base on directfb is links web browser.