object oClassType = Type.GetTypeFromProgID("SldWorks.Application"); Returns null value

Friends,

I am creating a C# application that takes an .sldasm file.

object oClassType = Type.GetTypeFromProgID("SldWorks.Application");

returns null value. What could be the reason.

I have installed solidworks 2009 in my machine.

Please  help

SolidworksApi macros