Harini,
Actually the version of the Lock-In Amplifier Start Up Kit that is on the web is outdated. The one that you should have gotten is the one that I am attaching below. We are currently fixing the link. This version will not have any licensing issues.
Please feel free to describe your application, like the type of measurements you are taking, how many channels you need, etc. I would be happy to be of further assistance.
Regards,
Claudia Lorente
Applications Engineer
National Instruments
http://www.ni.com/ask