Property getter was expecting a com.google.appinventor.components.runtime.Button component but got a YailList instead

From the error i guess that you are trying to use the any component blocks and the components are in a list.
But instead of the com.appinventor.components type of input (image ) you are simply sending such a component name - image .

For more help try sending your blocks or .aia here.

Also, look here -