Hi Ravi,
I am still facing same issue while connecting SAP HANA studio to AWS . Below are the steps as per http://scn.sap.com/docs/DOC-28294 and still no luck.
1) My instance is running in AWS
2) mapped elastic ip address to imdbhdb in host file
2) Getting the same as your screen shot error when trying to add system in studio. ( I was able to connect for first time but it did not work during 2nd log on.
Thanks
Siva