neither Turbotax nor the IRS keeps returns that old. I don't think the forms are available online or by phone so you'll have to request them by mail
https://webapp.ftb.ca.gov/contactus/home/formsbymail
do your best. I would also attach a statement that says "actual tax documents from 2006 are not available. i used my best effort to estimate the amounts reported"
are you sure it's actually from CA FTB, I mean almost 15 years is a long time for them to wait?
