Hi Lakshmi,
Was Gennadiy right about the disabled plug-in? If the plug-in is enabled, but the problem still persists, it seems that you've faced a known issue related to several Windows, MS Visual Studio, or .NET framework updates. We have created a patch for this TC 7.52 problem.
The situation is fixed in TestComplete 8. So, you can either try using the current version of the product, or get in touch with us via the Contact Support web form. We'll provide you with a fix for TestComplete 7.52. In your message, let us know the edition of the product (Standard or Enterprise) and the bitness of the problematic machine.