Hi Blaise,

I checked with the following command and I can see "scan", so laser is working right??
vros@ubuntu:~$ rostopic list
/clock
/diagnostics
/hokuyo_node/parameter_descriptions
/hokuyo_node/parameter_updates
/rosout
/rosout_agg
/scan
/time

Now I tried something different. I executed "$ rosrun hokuyo_node hokuyo_node" on the pioneer bot and for visualization on rviz I executed

"$ rosrun rviz rviz -d `rospack find hokuyo_node`/hokuyo_test.vcg" on my base computer [on which ROS master is running, I am connected to pioneer 

through ssh]

vros@ubuntu:~$ rosrun rviz rviz -d 'rospack find hokuyo_node' /hokuyo_test.vcg
[ INFO] 0.000000000: Loading general config from [/home/vros/.rviz/config]
[ INFO] 0.000000000: Loading display config from [/home/vros/.rviz/display_config]

[ERROR] 0.000000000: File [rospack find hokuyo_node] does not exist

As hokuyo_node is publishing to ROS master running on base computer [remote computer], hence rviz can subscribe to scan topic. Am I right?. Please 

tell me how to resolve this issue.

Thanks
Vinay