running several nodes in different machines using bash or python script

edit

• is ROS installed properly on each machine?
  • try rosrun on each machine directly
  • try ssh'ing into the other machine and running a ROS node e.g. rosrun image_view image_view , or rostopic list.
• work through the Turtlebot network configuration tutorial step by step
  • http://wiki.ros.org/turtlebot/Tutoria...
  • http://wiki.ros.org/Robots/TurtleBot/...

Other than using the ROS' dedicated feature like machine tag as @BennyRe suggests, I guess you better check if the environment variables are loaded properly on the shell on the remote host; the error message says the rosrun command isn't found, which is kind of common issue even on local hosts. You can still utilize sshpass for diagnose purpose like:

sshpass -p 'password' ssh user@host env|grep ROS

It looks as though ros is not fully installed on the machine you're ssh'ing into. It's probably easiest if you ssh in manually using a terminal and the same username and password. Then try the rosrun command from the terminal. If it still doesn't work then you know that it's the ros installation which is the problem

BennyRe is right you can achieve what you're aiming for using a ros launch file with a machine tag in it. This would be a neater and more 'ROS approved' way of doing thing. Although by the looks of it that won't solve this particular problem you're having.