Actually it is calculating the $600 credit but the Energy Efficient Home Improvement Credit Limit Smart Worksheet isn't calculating.  Line A is supposed to bring forward your tax liability to see if it is enough for the credit and it is coming back blank when my client has a $17k tax liability.  Therefore it is limiting the credit to zero because the form isn't inserting his tax liability.  It is tough getting returns out the door early when the forms are not working.  I guess I will have to contact Intuit.