Hi niti_c,
Welcome to the forum.
Can you provide more information?
What version of Inventor?
Is this a new install?
Did iLogic work in the past?
What have you tried so far?
Does this link help? :
http://forums.autodesk.com/t5/inventor-general-discussion/ilogic-activation-error/td-p/2756875
I hope this helps.
Best of luck to you in all of your Inventor pursuits,
Curtis
http://inventortrenches.blogspot.com