Hi Arun/swaroop
Thanks for your response 
I have tried the functionality on vanilla instance as well.
"ERRORCould not create Job to generate report." is the error message that i see on the page while generating reports
full read permissions for all folders and these are permissions provided Read, Modify, Create, Delete, Edit ACL, Read ACL on below paths
/libs/dam/gui/content/reports
/libs/dam/content/reports?
when i click on create button second time i could the below massage
"Report Generation has been initiated. You will be notified on successful completion."
Adobe Link suggests me admin can generate reports easily not sure about the other users that we create on aem instance with out admin privilegios