Hi sanjeev,
Can you go to solman_setup ->managed system setup and check the status of Plug-in for the system under test SID
A pre-requisite for the TAO setup to work is that managed system for which you try to establish connection the Plug-in status should be green.If status is not green please push the data from managed system rz70 to SLD and LMDB .
Also do you have CBTA frontend component(software)on your desktop
Regards,
Murali