Sorry Alexander, the FeatureCollection component is broken. This is why you see the internal error.
MIT intends to fix the FfeatureCollection control eventually, until then you can use this partial fix using blocks to work through part of the tutorial.
https://groups.google.com/forum/#!searchin/mitappinventortest/state$20quiz%7Csort:date/mitappinventortest/99Bajqq0Jqc/qxwz0MeeAwAJ Only the State part works with the method I used to work around the issue (I modified the json file) so the example works for the states quiz. You can get it to work with the state capitals by following the coding used in the state capitol Button event handler and providing the appropriate state capitol list.
Does it work for you? I expect MIT will have Companion 2.48 fixed by the start of 2019 ... this work around does work if you cannot wait.
Regards,
Steve