Construct 2 gives an error message when it uses the tokenat() expression on an element in an array. It seems to only happen in preview mode.
Here's the error.
This game is designed to build a room out of tiles by loading a JSON file.
The error does not seem to affect the room building process.
Room Building CAPX
Load the above CAPX and press 1, 2, 3 in that order to build the room.