I tried to execute example.world file that comes with Gazebo and everythings worked fine except for the guicam.
It showed me a blank image of the world no matter how I moved the robot.
The other windows like the position, power, laser and sonar seemed to work fine since there was a change on how values were read when I moved the robot in command mode although I didnt know what I was doing since I couldnt see the robot.
I tried to change the renderMethod in example.world to SGIX, GLX and XLIB but the same problem persists or I get an OpenGL error.