Is it possible to set up a scaffolding?
Chris your right by not using a ladder on a out of level surface. However pros come across this issue all the time. You can improved your ladder by installing a device on the ladder that fixes this issue for you safely. Many higher end ladders come with them, but you can purchase this and install on the one you have. Ladder leveling devices not only make it safer but increases the ability to use the ladder in more locations such on stairs and such. http://stores.buyladder-max.com/-strse-template/llhome/Page.bok?gclid=COjZ967LvLUCFUVN4AodIj8AJA
There are other types and brands but that link is just one of them. Simply Google Ladder levelers and you will be directed to them.
If you do not want to spend the money, simply rent a ladder from local rental shop that offers this device.
Just do not put any wood, bricks or home made supports that could fail.
Check with your local rental center as they may have a boom or similar lift you can rent by the day or half day.
Agree that adding leveling leg to your ladder is a good option here. Alternatively, maybe you could hire someone to come remove the shutters so you can paint them on the ground, then come back to reinstall them later... ??
I like Hamtil's idea. Is it possible to safely remove the shutters by reaching out from the second story windows?
how about scaffold? my husbands business is scaffolding and they use it anywhere. it adjust to levels and locks in place and you can tie off with a safety harness. find a business that rents them out in your area.