TypeError: undefined is not an object:

Help! I am new to PsychoPy and Pavlovia and seem to be running into issues when trying to pilot my experiment. I am able to read the first instructions and hit the space bar to start my study then this appears. I also have no idea where to look for this error.

Do you have anything called this or size of an array at that point in the experiment?

I could not find anything but also unsure where to look? In the code?

Have a look at my crib sheet (pinned post) to see how to activate developer tools. You might then be able to get a line number in the JavaScript for the error.