I was trying to visualize hokuyo laser data in rviz while using hokuyo_node. Below is the error I am getting..... I need some suggestions although error is mentioned in the troubleshooting of RVIZ http://www.ros.org/wiki/rviz/Troubleshooting but still not clear.

[please note that I am getting the same error if I just call $rosrun rviz rviz]:
vros@powerbot:~$ rosrun rviz rviz -d 'rospack find hokuyo_node' /hokuyo_test.vcg
[ INFO] 1278719927.352134000: Loading general config from [/home/vinaypilania/.rviz/config]
[ INFO] 1278719927.353486000: Loading display config from [/home/vinaypilania/.rviz/display_config]
rviz: OgreGLSupport.cpp:57: virtual void Ogre::GLSupport::initialiseExtensions(): Assertion `pcVer && "Problems getting GL version string using glGetString"' failed.

This error is mentioned in the troubleshooting. According to troubleshooting Do I need to install graphics driver compatible to my laptop for ubuntu 9.04 or to install OpenGL. Please not that I have installed ROS on other computer there I am not getting this error [only for $ rosrun rviz rviz ] but there I tested slam_gmapping package in the tutorial http://www.ros.org/wiki/slam_gmapping/Tutorials/MappingFromLoggedData.

In the end of this tutorial in "3. Variation: watching the mapping progress", I am getting one error that is "graphics driver does not support 2000*2000" grid/array [approx]. From all these testing it seems that there is some problem with rviz.