2011/9/12 Rômulo Cerqueira <romulo.cerqueira@ufba.br>

when I try to execute Player/Stage, I have this error:

romulo@baea ~ $ robot-player /opt/stage/worlds/simple.cfg
Registering driver
Player v.3.0.2

* Part of the Player/Stage/Gazebo Project [http://playerstage.sourceforge.net].
* Copyright (C) 2000 - 2009 Brian Gerkey, Richard Vaughan, Andrew Howard,
* Nate Koenig, and contributors. Released under the GNU General Public License.
* Player comes with ABSOLUTELY NO WARRANTY.  This is free software, and you
* are welcome to redistribute it under certain conditions; see COPYING
* for details.

error   : Failed to load plugin stageplugin.
error   : libtool reports error: file not found
error   : plugin search path: /home/romulo:/opt/stage/worlds:/usr/lib/:/usr/lib/robot-player
error   : failed to load plugin: stageplugin
error   : failed to parse config file /opt/stage/worlds/simple.cfg driver blocks

How I can fix it?

I believe you need to set the PLAYERPATH environment variable to point to the lib directory containing the player files. Alternatively, I've had this error occur when a plugin loaded by player crashes during initialisation - if you have any custom plugins loaded by the configuration file, check those for errors.