Hi Kishore,
You can find the list of supported Infragistics controls in the "Working With Custom Controls" help topic. If the controls you use are not on the list, you can try working with the controls via their native properties and methods available to TestComplete.
If you still have some issues, please let us know the controls' names and versions. We'll try to help you with appropriate suggestions or script samples.
BTW, the latest version of the product is TestComplete 7.52. The update is available for downloading from our web site and the ClientServices portal (
https://clientservices.automatedqa.com/).