I was running rviz plugin turoial in moveit, but as i press plan inside rviz, i get error:

[ERROR] [1471947311.840651367]: No planning plugin loaded. Cannot plan.
[ WARN] [1471947311.907169887]: Fail: ABORTED: Unknown event

Although other people also has asked same question i didnt get the exact working answer for me. I am using ros indigo.