Hi.I am using ROS fuerte on Ubuntu 12.04. While I was running erratic on gazebo, using

 roslaunch erratic_navigation_apps demo_2dnav_slam.launch  

I encountered the following warnings.

[ WARN] [1354625870.495205787, 49.740000000]: Message from  
[/base_laser_self_filter] has a non-fully-qualified frame_id [base_footprint].  
Resolved locally to [/base_footprint].  This is will likely not work in 
multi-robot systems.  This message will only print once.
[ WARN] [1354625870.495682174, 49.740000000]: Message from 
[/base_laser_self_filter] has a non-fully-qualified frame_id [base_footprint]. 
Resolved locally to [/base_footprint].  This is will likely not work in 
multi-robot systems.  This message will only print once.
[ WARN] [1354625910.922358012, 65.418000000]: The /base_scan/marking observation 
buffer has not been updated for 0.24 seconds, and it should be updated every 
0.20 seconds.
[ WARN] [1354625988.636103668, 91.693000000]: The /base_scan/marking observation 
buffer has not been updated for 0.21 seconds, and it should be updated every 
0.20 seconds.
[ WARN] [1354625993.083708417, 93.493000000]: The /base_scan/marking observation 
buffer has not been updated for 0.20 seconds, and it should be updated every 0.20 
seconds.
[ WARN] [1354625996.023810230, 94.695000000]: The /base_scan/marking observation 
buffer has not been updated for 0.20 seconds, and it should be updated every 0.20 
seconds.

In RVIz, I am unable to visualise the robot_footprint and other sensor's data. My guess is that the warnings are the reasons for that. Any ideas how can I resolve this? Thank you.

Update

I sort of by-pass the

[ WARN] [1354625993.083708417, 93.493000000]: The /base_scan/marking observation 
buffer has not been updated for 0.20 seconds, and it should be updated every 0.20 
seconds.
[ WARN] [1354625996.023810230, 94.695000000]: The /base_scan/marking observation 
buffer has not been updated for 0.20 seconds, and it should be updated every 0.20 
seconds.

warnings by setting the expected update frequency higher.

However, the RViz still sort of "freeze". The ROS time elapsed is always zero. I think I will ask another question on this.