Roof/Wall Height

[JoAnn]

Now I'm confused. You seem to have changed a lot of your dimensions.
It also appears that you have removed the exterior walls at the top left corner, and these are needed for the bottom of the roof to rest upon.
Knee walls are meant to be interior walls. Fix that and the error messages will probably go away.
Google 'knee wall' and look at all the images shown to get a better idea of what they are.

Also, a section of your front porch (in the real house pic) shows that it does not have a roof over it (the door area on the side wall of the garage). You should partition it with an invisible railing, so that you can select that area of the deck and specify 'no roof over this room'. That section of porch roof might interfere with the roof that you are trying to fix.