Hi Roshan,
Have you checked if it's an authorization issue (SU53)?
System is checking for authorization object K_TKA50 : CO: Planner Profiles . Make sure you have all required activities to execute CJR2.
OR
Analyze it in one more way :
Go to SE80 ->Select 'Program' and enter SAPLKPP6 under it. -> select 'Screens' 1007->double-click (F8)->Continue and check for Planner profile here. (Mine is SAPALL here)->F4 and go to the customizing of 'User-defined planner profiles' and analyze if there is any authorization group which is restricting you in executing CJR2.
Hope it helps.
Regards
Saurabh