Case Learn Problem

Here's what I'm having issues with. I've put a 5.3 from a 2005 Yukon into a 1940 chevy coupe. Everything worked out great until I started having some weird hard start issues. I've replaced the MAP, Crank and cam sensors and have it back running but I'm getting random misfire codes. I'm thinking I need to do a case learn but my button is greyed out. I've followed all the steps under the help menu with no luck. The only thing I don't have is a parking brake. Would this cause issues? Oh yea, I downloaded the latest software last night.

Thanks
Robert

Update, I saw where you need to switch to metric units do use this feature. I've done this and still nothing. Button is still greyed out and I do not get any engine info displayed on the page. Can anyone help?

Robert